I was not surprised to hear

I was not surprised to hear that Harry had failed his driving test.
A. By having failed his driving test, Harry made no surprise.
B. It came as no surprise to me that Harry had failed his driving test.
C. Harry's having failed his driving test is not my surprise.
D. If Harry had not failed his driving test, I would have been surprised.
I know that the answer is "B". But why not "D"?: If Harry hadn't failed his driving test, I would have been surprised. I need a detailed explanation for this. Who can help me? Thanks in advance.