A man and his wife had a small restaurant near a station. The restaurant often stayed open until after midnight, because people came to drink and have meals while they were waiting for trains. At two o'clock one morning, a farmer was still sitting at a table there. He was asleep. The wife of the owner of the restaurant was very sleepy and wanted to go to bed. She looked at the farmer several times and waited for him to wake and go, but each time she looked at the farmer, he was still there sleeping. Then at last she went to her husband and said to him, "You have wakened him six times now, but, why haven't you sent him away? It's very late." "Oh, no, I don't want to send him away," answered her husband. "You see, whenever I wake him up, he asks for his bill, and when I give him the bill, he pays it and then goes to sleep again." 

Why was the farmer asleep at a table?

A.Because he had missed the train.

B.Because he was too tired.

C.Because he was drunk.

D.The story does not tell us.