Which of the Following Examples Does NOT Illustrate a Difference

Which of the following examples does NOT illustrate a difference in fitness that would lead to evolution by natural selection?

A) Male peacocks with larger, more colorful tails are more frequently chosen as mates.
B) Moths with coloration that allows them to blend in with the bark of spruce trees are more difficult for predators to find.
C) Wolves who are more successful hunting in packs find mates more frequently.
D) A female panda living in a zoo in China is impregnated more frequently than a female panda living in a zoo in the United States.