Which of the Following Is an Example of a Trophic

Which of the following is an example of a trophic cascade?

A) A mountain lion preys upon deer and as a result the abundance of a grass species dramatically increases.
B) A large population of European rabbits grazes on an annual weed species and dramatically reduces their population.
C) A marine mammal feeds on baleen and significantly reduces their abundance in the Pacific Ocean.
D) A plant virus reduces the number of native plants in a community.