Read the following conversation and answer the question.

W: I wonder if Henry is coming.

M: We're supposed to be here at eight sharp. He told me he would be here at eight o'clock, and it's already half past eight.

W: Perhaps something is wrong with him.

Question: How long have the speakers been waiting? 

- For 30 minutes.

- For 60 minutes.

- For 90 minutes.


For 30 minutes.