SHE WAS SO BUSY THAT SHE COULDN’T ANSWER THE PHONE

37. She was so busy that she couldn’t answer the phone.

A. Because she was very busy, she couldn’t answer the phone.

B. Because she was very busy, she could answer the phone.

C. Although she was very busy, she couldn’t answer the phone.

D. Although she was very busy, she could answer the phone.