an increased loudness of sound a reflection of sound an increased frequency of sound a refraction of sound
I gave my students this multiple choice question: A student in an empty classroom shouts, "Hello!" Which best explains what the student hears after the shout?

Only one answer is correct among these 4 choices:
- an increased loudness of sound
- a reflection of sound
- an increased frequency of sound
- a refraction of sound

Could you tell me which one is correct?

a reflection of sound