(A)The effects of genetic drift are most apparent in small populations.
(B)Evolution and natural selection is most prominent in populations having no variations.
There are no populations that do not have any variations instead, populations are formed when organism of the same species having variations live together and interact with each other in a specific geographical area.
Genetic drift can be defined as the variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce. Genetic drifts occur in populations of all sizes, but their effects are most apparent in small populations.
So, teh correct answer is 'Only (A) is correct'.