Eastern Tent Caterpillars Are Social Nesters That Spin Weblike Nests

Eastern tent caterpillars are social nesters that spin weblike nests, or tents, to which they keep adding layers as they molt and grow.The caterpillars leave the tent several times each day to feed on the leaves of their host tree.Many potential predators will attack one tent caterpillar and then refrain from attacking or eating others.Two possible deterrents to predation are the stiff hairs present on caterpillars (but not pupae) and toxic cyanide compounds, which caterpillars absorb from cherry trees where they nest and feed.Researchers wish to determine whether either of these actually deters predators.Which study design would most clearly distinguish between the two possible deterrents?

A) Offer only pupae to predators.
B) Offer both the toxic caterpillars and their pupae to predators.
C) Raise caterpillars on nontoxic leaves, and offer only nontoxic caterpillars to predators.
D) Raise some caterpillars on nontoxic leaves, and offer both toxic and nontoxic caterpillars to predators.
E) Raise some caterpillars on nontoxic leaves, and offer both toxic and nontoxic caterpillars and pupae to predators.