If birds did not have wings, they would not have been able t

[BTGmoderatorAT]

If birds did not have wings, they would not have been able to fly

A. If birds did not have wings, they would not have been
B. If birds had no wings, they would not have been
C. Unless birds had wings, they would not be
D. If birds did not have wings, they would not be
E. Unless birds had wings, they would not have been

What's the correct option? I think the option C is right

[Vincen]

I think that answer should be B.

Experts, could you clarify this for us?