Competitive Exclusion States That Two Organisms Cannot Indefinitely Occupy the Same

Competitive exclusion states that two organisms cannot indefinitely occupy the same niche when resources are limited. When this does occur, organisms tend to show some sort of competitive coexistence. Which of the following is an example of competitive exclusion?

A) Songbirds pick different nesting sites.
B) Manatees consume all the native grasses in a lagoon.
C) Oak trees and pine trees live in the same forest.
D) Wildebeests and zebras graze on the same savannah.