One evening in November, Berlin received a telephone call from Mrs. Green. "Please, Dr Berlin, come to my house. I had 50,000 dollars on my desk and now it is gone." Dr Berlin arrived at Mrs. Green's house at eight o'clock. First he asked Mrs. Green, "When did you see the money last?" "At seven o'clock. I put it on my desk in my living room. Then I went to wash my hair. I came back at seven thirty and the money was gone." "I see." Dr Berlin said. "Were you alone in the house?" "No. My sister's son Jack is here, too." Then Dr Berlin and Mrs. Green went to Jack's room. "Please, sit down," Jack said. Dr Berlin sat on the only chair in the room, and the chair was cold. He also saw some books on the ground near his feet. "What have you been doing this evening?" Dr Berlin asked. "I came home at six-thirty, and went right to my room. I've been sitting in that chair and reading all the evening. I never got up and I never left the room. Maybe somebody came into the house and took my aunt's money." After hearing that, Dr Berlin was clear about who had taken the money. When did Dr Berlin answer the phone from Mrs. Green?
At 6:30 At 7:00 After 7:30 At 8:00