Which of the following statements is consistent with the principle of competitive exclusion?

a) bird species generally do not compete for nesting sites.
b) the random distribution of one competing species will have a positive impact on the population growth of the other competing species.
c) two species with the same fundamental niche will exclude all other competing species.
d) even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of two competing species.
e) natural selection tends to increase competition between related species.