Intrasexual selection is the act of competing with other members of one's own sex for various reasons such as high status, mating, area, and many more as well as the evolutionary process responsible for this competition. The great examples of these are antlers of deers and big size showy feathers of the peacocks to attract their males.
Thus, the correct answer is - intrasexual selection.
Since it will help the individual live longer, there is a greater chance that it will reproduce than those with lesser favorable traits. Thus the next generation will resemble the parents with the favorable triat more.
