The Polygyny Threshold Model (PTM).
Since females can fertilize all her eggs in one mating, they tend to track resources rather than mates.
PTM predicts that females choose mating systems based on
resources available in territories controlled by males.
In choosing between
A and
B, which has only a slight advantage in resources, she should choose the monogamous
A since she will not have to share the resource with another female and thus gains greater
fitness.
In choosing between
A and
C, the relative fitness of the 2 territories are the same,
and she is equally likely to choose either mating system.
In choosing between
A and
D, she should choose the polygynous
D because her share of its quality,
even when shared among several females, has exceeded the "polygyny threshold".