单项选择题

Directions: In this section you will hear two mini-talks. At the end of each talk, there will be some questions. Both the talks and the questions will be read to you only once. After each question, there will be a pause. During the pause.
Which of the following is not mentioned as responsible for sneezing

A. Pollen.
B. Dust.
C. Bright light.
D. Kitchen.