【单选题】

On the TrainThe night train from Glasgow was so crowded thatDonald, who was on his way to London to find a temporary job for the university vacation, wished that he had decided to travel by day. He had never been so hard up.He got on the train and walked along the corridor of the second-class compartments. He couldn’’t find a seat anywhere. He could not afford to travel first class, and he did not want to stand in the corridor. Neither did he want to sit on his suitcase. He was so tired that he decided to sit down in a first class compartment at least for a while. He soon found one with a single occupant (乘客) , a gentleman reading documents from a briefcase. With the self-assurance of a first class traveler, he opened the door and went in. No sooner had he sat down than the ticket inspector arriveD、What bad luck! Now he would have to pay the excess (额外的) fare.As he turned out his pocket to find enough money he saw the gentleman was watching him with amusement. It was humiliating (令人感到羞辱的). However, he was so tired that he soon fell asleep.Presently, hearing a noise, he half opened his eyes. Not only did he notice that his traveling companion had gone, but he also saw that a rough-looking man was searching through the businessman’’s briefcase.Donald grabbed the briefcase and wrenched (猛夺) it free, kicking at the man’’s leg. The man fleD、Then the businessman returned and foundDonald holding the briefcase and peering inside it.Donald realized that he was in quite an awkward situation, but the man was smiling. Nor was this the only surprising thing. Not only was the gentleman (who introduced himself as Mr. Smith) smiling, but he thankedDonald warmly. On his way back to the compartment, Mr. Smith had seen the man leaving in a great hurry. He had so quickly assessed the situation that he knewDonald was innocent.Only after a long chat, in whichDonald was asked many questions about himself, didDonald discover that Mr. Smith was in fact managing director of a large factory in London.Donald had never imagined that this strange incident would help him to find a job, but just as they were leaving the train, Mr. Smith offered him the post of temporary Night Security Officer for his factory. Mr. Smith realized thatDonald was innocent______.

A、after he had swiftly evaluated the situation
B．before he met the fleeing man
C．after he had a long chat withDonald
D．after he checked the briefcase