Scientists Have Hypothesized That Resource Competition May Facilitate Sympatric Speciation

Scientists have hypothesized that resource competition may facilitate sympatric speciation. These graphs illustrate two scenarios: graph A illustrates a normal distribution of both beak size and seed size, while graph B illustrates a normal distribution of beak size but a flat distribution of seed size. Which graph illustrates resource competition?

A) Graph A illustrates resource competition; different seed sizes have led to the distribution of different beak sizes, so all birds get approximately the same amount of food.
B) Graph A illustrates resource competition; different beak sizes led to the distribution of different seed sizes, so all birds get approximately the same amount of food.
C) Graph B illustrates resource competition; because there are equal numbers of seeds available across the size range.
D) Graph B illustrates resource competition; because there are more medium-beaked birds, there is more competition for medium-sized seeds.