Consider a species of aquatic fish that produce a defensive chemical when a predator is nearby. The chemical protects the group, including relatives, from predators but also has a metabolic cost to the fish producing it. In this species, individuals in the population have four phenotypes for the amount of chemical they produce, arranged in order from P < Q < R < S. The graph below gives the cost and benefit functions for chemical production for the four phenotypes.

Which of the following phenotype frequencies represents the correct outcome of natural selection?