Refer to the Figure

Refer to the figure.
The figure shows a matrix of fitness payoffs for interactions between two behaviorally different types of gulls: those that always fish for themselves and those that sometimes steal fish from others. P stands for the baseline fitness that a gull derives when it fishes for itself. B is the fitness gained by a thief when it steals a fish from a fish-for-self type. C is the fitness cost associated with an attempt to steal a prey.
What causal question is the model designed to answer?

A) How can a hereditary thief phenotype spread in a population of fish-for-self types?
B) What are the fitness costs and fitness benefits of fish-for-self versus thief phenotypes?
C) When can group selection cause evolutionary change to take place?
D) What are the circumstances under which maladaptive traits can take over a population?