I know the answer but can you explain why fly wings are not homologous and the others are?

I know the answer but can you explain why fly wings are not homologous and the others are?

Four of the five wings below are homologous. Select the exception. (FLY)

a.    bat

b.    chicken

c.    fly

d.    penguin

e.    pterosaur

Same. Why A (are predictable) is the correct answer and why the others are incorrect.