Mark the letter A, B

Câu hỏi: 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.

A. Because I was busy doing my homework, I could not help my mother with the washing-up.

B. It was impossible for me to do my homework although my mother helped me with the washing-up. 

C. I could not help my mother with the washing-up until I finished my homework.

D. I could not do my homework because I had to help my mother with the washing-up.