Consider an advantageous allele segregating in a population as a major polymorphism. which of the following would not generally slow the fixation of the allele?
a. the environment changes in such a manner as to reduce the selective advantage.
b. the population begins to receive immigrants from a population that maintains the same initial frequency of the alleles.
c. in addition to being advantageous the allele also exhibits overdominance.
d. the population begins to exhibit positive assortative mating for each of the genotypes.
e. the population size increases.