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.
Mary knew how busy I was. She offered to help me.
A. Because Mary knew my business, she offered to help me.
B. Knowing how busy I was, Mary offered to help me.
C. Mary knew how I was busy and offered to help me.
D. Having known how busy I was, Mary offered to help me.