I did not see Susan off at the...

Câu hỏi: I did not see Susan off at the airport. I feel bad about it now.

A. I could have seen Susan off at the airport.

B. If only I had seen Susan off at the airport.

C. That I did not see Susan off at the airport escapes me now.

D. It suddenly dawns on me that I should have seen Susan off at the airport.