Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Example input: Context: Architecturally, the school has a Catholic character. Atop the Main Building's gold dome is a golden statue of the Virgin Mary. Immediately in front of the Main Building and facing it, is a copper statue of Christ with arms upraised with the legend 'Venite Ad Me Omnes'. Next to the Main Building is the Basilica of the Sacred Heart. Immediately behind the basilica is the Grotto, a Marian place of prayer and reflection. It is a replica of the grotto at Lourdes, France where the Virgin Mary reputedly appeared to Saint Bernadette Soubirous in 1858. At the end of the main drive (and in a direct line that connects through 3 statues and the Gold Dome), is a simple, modern stone statue of Mary. 
 Question: To whom did the Virgin Mary allegedly appear in 1858 in Lourdes France?
Example output: Saint Bernadette Soubirous
Example explanation: This is the correct answer. Because the question is asking for the name of the person and following sentence from the passage answers it: It is a replica of the grotto at Lourdes, France where the Virgin Mary reputedly appeared to Saint Bernadette Soubirous in 1858.
Q: Context: A sexually transmitted infection (STI) is a disease that spreads mainly through sexual contact. STIs are caused by pathogens that enter the body through the reproductive organs. Many STIs also spread through body fluids such as blood. For example, a shared tattoo needle is one way that some STIs can spread. Some STIs can also spread from a mother to her infant during birth. STIs are more common in teens and young adults than in older people. One reason is that young people are more likely to engage in risky behaviors. They also may not know how STIs spread. Instead, they may believe myths about STIs, like those in Table 22.1. Knowing the facts is important to prevent the spread of STIs. Myth If you are sexually active with just one person, then you cant get STIs. If you dont have any symptoms, then you dont have an STI. Getting STIs is no big deal, because they can be cured with medicines. Fact The only sure way to avoid getting STIs is to practice abstinence from sexual activity. Many STIs do not cause symptoms, especially in fe- males. Only some STIs can be cured with medicines; others cannot be cured. A number of STIs are caused by bacteria. Bacterial STIs can usually be cured with antibiotics. However, some people with bacterial STIs may not have symptoms so they fail to get treatment. Left untreated, these infections may damage reproductive organs and lead to an inability to have children. Three bacterial STIs are chlamydia, gonorrhea, and syphilis. Chlamydia is the most common bacterial STI in the U.S. Females are more likely to develop it than males. Symptoms may include burning during urination and a discharge from the vagina or penis. Gonorrhea is another common bacterial STI. Symptoms may include painful urination and a discharge from the vagina or penis. Syphilis is a very serious STI but somewhat less common than chlamydia or gonorrhea. It usually begins with a small sore on the genitals. This is followed a few months later by a rash and flu-like symptoms. If syphilis isnt treated, it can eventually damage the heart, brain, and other organs and even cause death. Several STIs are caused by viruses. Viral STIs cant be cured with antibiotics. Other drugs may help control the symptoms of viral STIs, but the infections usually last for life. Three viral STIs are genital warts, genital herpes, and AIDS. Genital herpes is a common STI caused by a herpes virus. The virus causes painful blisters on the penis or near the vaginal opening. The blisters generally go away on their own, but they may return repeatedly throughout life. There is no cure for genital herpes, but medicines can help prevent or shorten outbreaks. Acquired Immunodeficiency Syndrome (AIDS) is caused by human immunodeficiency virus (HIV). HIV destroys lymphocytes that normally fight infections. AIDS develops if the number of lymphocytes drops to a very low level. People with AIDS come down with diseasessuch as certain rare cancersthat almost never occur in people with a healthy immune system. Medicines can delay the progression of an HIV infection and may prevent AIDS from developing. Genital warts is an STI caused by human papilloma virus (HPV), which is pictured in Figure 22.15. This is one of the most common STIs in U.S. teens. Genital warts cant be cured, but a vaccine can prevent most HPV infections. The vaccine is recommended for boys and girls starting at 11 or 12 years of age. Its important to prevent HPV infections because they may lead to cancer later in life. Other reproductive system disorders include injuries and noninfectious diseases. These are different in males and females. Most common disorders of the male reproductive system involve the testes. They include injuries and cancer. Injuries to the testes are very common. In teens, such injuries occur most often while playing sports. Injuries to the testes are likely to be very painful and cause bruising and swelling. However, they generally subside fairly quickly. Cancer of the testes is most common in males aged 15 to 35. It occurs when cells in the testes grow out of control and form a tumor. If found early 
 Question: In which of the following age groups are STIs most common?
A:
teens and young adults