The shortest course is _________.

A．if the detectives hadn't questioned so many people in Atlanta and in Los Angeles
B．if it detectives hadn't watched railway stations, hotels and airports
C．if it hadn't been for the help of the Canadian police
D．if the murderer hadn't worn thick glasses

A．Sneyd used a Canadian passport
B．he was sure that Sneyd was James Earl Ray
C．Sneyd's name was on the passenger list
D．Sneyd looked like Ray