Task: Question Answering
Input (English): Passage: I wrote a letter to a friend the other day , and then had to mail it . Before I could send it I needed a few things . I needed an envelope , to put the letter in . I went to post office and bought the right size envelope for a letter and the right type of stamp . I wrote my name and address in one corner . I wrote the name and address of the person I was sending the letter too in the middle . I made sure the letter was sealed in by the sticky glue of the envelope . I put the stamp on the outside of the envelope , on the corner . I took my envelope and walked to the out going mail box at the post office . I left the post office and went home . Question: When did they pay for the letter? Option1: At the post office Option2: after they went home
Output (English): At the post office