Detailed Instructions: In this task, you are given a question and answer options for that question. Using this information, you have to classify each text into different topics: medicine, nursery, psychology, chemistry, pharmacology, biology.
Q: Question: In toxicology, the probability of adverse effects, harmful to health, from exposure to a toxic agent is known as: 
 Options:  <0> Danger. <1> Exposition. <2> Risk. <3> Answer. <4> Effect.
A:
pharmacology