单项选择题

Questions 8 to 10 are based on the following conversation. At the end of the conversation, you will be given 15 seconds to answer the questions.
Now, listen to the conversation. What are the speakers mainly discussing

A.Why Tom needs to get glasses.
B.Research Tom has done for his chemistry paper.
C.The disadvantages of working in an office.
D.How using a computer can affect one’s eyes.