Mating fiddler crabs use several types of sexual selection. males battle each other for territory using their greatly enlarged claws. the territories preferred by females are those in the most physiologically stressful area, and only healthy males can maintain them for long. the males also raise their claws to signal femailes; those that reach the greatest heights are most noticeable becasue females are attuned to look upwards for predators. which model of sexual selection is least likely to impact this mating system.
a. good genes mechanism
b. direct benefits
c. sensory bias
d. male - male competition
e. all of these models apply to the scenario equally well

All of these models apply to the scenario equally well.

Explanation:

Firstly, the male crabs battle each other for territory using their greatly enlarged claws. This clearly depicts male-male competition.Secondly, Females choose to mate with only those male who are fit to survive in stress full condition. Thus female look for good genes that would enable her offspring to survive in stressful condition. Here Good gene mechanism applies.Thirdly, The presence of large claws make it more noticiable to female and stronger to compete with other males. Thus this is a direct benefit.Lastly, we see that female crab have a tendency to look up for their prey and this tendency is well exploited by male crabs who raise their claws to a heigh so that they get noticed by the female.