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. My father locked all the doors. He went to wor

Before my father went to work, he had locked all the doors.

After my father had gone to work, he locked all the doors.

Before my father locked all the doors, he went to work.

Before my father had gone to work, he locked all the doors.