For Many Years, No One Bothered to Test the Food-Competition

Multiple Choice

For many years, no one bothered to test the food-competition hypothesis for why giraffes have long necks. Why?

A) It had been much too difficult to test.
B) The hypothesis was so plausible that no one thought to question it.
C) They tried, but the results were inconclusive.
D) The hypothesis did not make clear predictions that could be tested.