When Mosquitoes Are Abundant, Purple Martins Flock to the Area

When mosquitoes are abundant, purple martins flock to the area and feed exclusively on them. When mosquito populations are not large, purple martins are similarly scarce and feed on other insects. This is an example of

A) density- independent regulation.
B) exotic regulation.
C) density- dependent regulation.
D) community carrying capacity.
E) ecosystem carrying capacity.