The closest combination in meaning to the sentence: “He realized that he had missed the last train. He began to walk.” is ______.
A.Realized that he had missed the last train, he began to walk
B.Realizing that he had missed the last train, he began to walk
C.Began to walk, he realized that he had missed the last train
D.Being realized that he hind missed the last train, he began to walk