Answer:
The correct answer is a: The community was under top-down control
Step-by-step explanation:
Top-down control refers to scenarios where superior predators control the structure and dynamic of an ecosystem. These systems are affected by the presence/absence of the superior predator influences all the lower links in the trophic chain.
In the exposed example wolves, that are considered to be the top predators, affected the white-tailed deer populations being the cause of its decrease. As wolves used to feed on white-tailed deer, they kept these populations under control, but once the wolves got extinct, the deer population increased again. Probably, this explosion in the deerĀ“s population also affected its lower link in the trophic chain.