The answer would be: C) sexual selection.
Sexual selection happens where one of the individuals choose the partner to sex based on some criteria. In this case, the ability to have a beautiful bower will determinate the ability of the bird to have sex and produce offspring. The criteria are not limited to visual. It could be diverse in other cases, like a deeper croak in frog
GG bb
gg GGgg bbgg
Bb GGBb bbBb
does this make sense ? I tried to set up the square best I can
Answer: population
hope this helped