In evaluating the wings of the listed animals, the focus is on whether they share a common evolutionary origin, which defines homologous structures. The wings of a bat, chicken, penguin, and pterosaur are all modifications of the forelimb, demonstrating a common ancestry among vertebrates. However, the wing of a fly is fundamentally different.
Fly wings are not derived from the same skeletal structures as those of the other animals; instead, they are an example of convergent evolution where unrelated species develop similar traits. Therefore, the exception in this case is c) fly.