A Researcher Discovered a Species of Moth That Lays Its

A researcher discovered a species of moth that lays its eggs on oak trees. Eggs are laid at two distinct times of the year: early in spring when the oak trees are flowering and in midsummer when flowering is past. Caterpillars from eggs that hatch in spring feed on oak flowers and look like oak flowers, but caterpillars that hatch in summer feed on oak leaves and look like oak twigs.
How does the same population of moths produce such different-looking caterpillars on the same trees? To answer this question, the biologist caught many female moths from the same population and collected their eggs then put at least one egg from each female into eight identical cups. The eggs hatched and at least two larvae from each female were maintained in one of the four temperature and light conditions listed below.
$$\begin{array} { | l | l | } \hline \text { Temperature } & \text { Day length } \\\hline \text { Springlike } & \text { Springlike } \\\hline \text { Springlike } & \text { Summerlike } \\\hline \text { Sumnerlike } & \text { Springlik } \\\hline \text { Summerlike } & \text { Summerlike } \\\hline\end{array}$$
In each of the four environments, one of the caterpillars was fed oak flowers, the other oak leaves. Thus, there was a total of eight treatment groups (4 environments × 2 diets) .
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Which one of the following is not a plausible hypothesis that can be tested in this experiment?

A) The longer day length of summer trigger the development of twig-like caterpillars.
B) The cooler temperatures of spring trigger the development of flower-like caterpillars.
C) Differences in air pressure, due to differences in elevation, trigger the development of different types of caterpillars.
D) Differences in diet trigger the development of different types of caterpillars.