Which of the Following Is an Example of Phenotypic Plasticity

Which of the following is an example of phenotypic plasticity?

A) In a population of peppered moths, the wings of some individuals are speckled, while those of others are uniformly dark.
B) Male reindeer grow a new set of antlers at the beginning of each breeding season. As a male grows older, he grows larger antlers with more branches.
C) Individuals of a particular species of intertidal barnacle have a short, squat body form in low-density populations and a tall, thin body form in high-density populations.
D) Whales migrate each year to breed in warmer water.
E) Over a number of generations the coat colour of a population of feral rabbits becomes noticeably darker.