Aspecies of plants that adapts to become more tolerant of toxic heavy metals produced as a result of human mining activities is an example of

a. stabilizing selection

b. disruptive selection

c. directional selection

d. mutation

C

Explanation:

This kind of selection favours the individuals on one end of an extreme trait in a population. In this case the extreme trait is a high tolerance for heavy metals. The individuals on this extreme end, therefore, survive more than the rest of the population and are able to pass their genes to the subsequent generations.With every generation, there are more and more individuals that  are tolerant of heavy metals leading to an evolution of the species towards tolerance to heavy metals.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).   so the answer is a.