Refer to the Figure

Refer to the figure.
This work would be based on optimality theory if the

A) researchers expected that pelicans would, when possible, minimize their flight expenses.
B) fitness benefit derived from flying in a V-formation exceeded the cost of the behavior.
C) researchers had tested the prediction that other large, flock-forming species would also fly in V-formations under some conditions.
D) researchers believed that every aspect of pelican behavior was an adaptation, that is, an ideal solution to an environmental problem of some sort.