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.
I didn’t know that you were at home. I didn’t drop in.

A. I didn’t know you were at home although I didn’t drop in.

B. Not knowing that you were at home, I didn’t drop in.

C. If I knew that you were at home, I would drop in.

D. Not knowing that you were at home, but I still dropped in