Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions The trains began to pull out. Most...

A. The passengers, most of them were full of, began to pull out the trains

B. The trains, most of which were full of passengers, began to pull out

C. The trains, most of whom were full of the buses, began to pull out

D. The trains, most of them were full of passengers, began to pull out