Read the following conversation and answer the question.

W: Okay, class. I'll collect your homework now. Bob? Where is your homework?

M: I'm sorry, Mrs. Murphy. I couldn't do it. I had a stomachache last night.

Question: Why didn't Bob finish his homework? 

- He was lazy.

- He had too much homework.

- He had a stomachache.


He had a stomachache.