单选题　　It was fifteen past nine as Marie hurried into the office building where she was going to work Her bus had inched along through heavy morning traffic, making her a few minutes late for her very first job. She decided to start out half an hour earlier the next day. 　　Once inside the lobby, she had to stand at the elevators and wait several minutes before she could get on one going to the sixth floor. When she finally reached the office marked "Smith Enterprises", she knocked at the door nervously and waited. There was no reply. She tapped on the door again, but still there was no answer. From inside the next office, she could hear the sound of voices, so she opened the door and went in. 　　Although she was sure it was the same office she had been in two weeks before when she had the interview with Mr. Smith, it looked quite different now. In fact, it hardly looked like an office at ail. The employees were just standing around chatting and smoking. In the front of the room, somebody must have just told a good joke, she thought ,because there was a loud burst of laughter as she came in. For a moment she had thought they were laughing at her. 　　Then one of the men looked at his watch, clapped his hands and said something to the others. Quickly they all went to their desks and, in a matter of seconds, everyone was hard at work. No one paid any attention to Marie. Finally she went up to the man who was sitting at the desk nearest to the door and explained that this was her first day in the office. Hardly looking up from his work, he told her to have a seat and wait for Mr. Smith, who would arrive at any moment. Then Marie realized that the day'' s work in the office began just before Mr. Smith arrived. Later she found out that he lived in Connecticut and came into Manhattan on the same train every morning, arriving in the office at 9:35,so that his staff knew exactly when to start working.