Each of them is right about one, so if A and B are right, Xiaoling's "A, B and B" are all wrong, which is not true.

So A is right in the first place and B is wrong in the second place.

Xiao Hong is wrong about push-ups and Ding is right.

Ding concluded that Xiao Gang said only C, and the second one was right.

To sum up, A comes first, C comes second, B comes third and D comes fourth.