What Was the Researcher's Conclusion in the "Ant Plant" Studies

What was the researcher's conclusion in the "ant plant" studies?

A) Tramp ants that occupy domatia, protect the trees from herbivores.
B) Nectar attracts herbivores and prevents them from eating the leaves.
C) Any ants that occupy domatia, protect the trees from herbivores.
D) Herbivores are more likely to eat the leaves of plants with domatia.
E) Tramp ants eat the leaves of plants with domatia.