Answer:
(A) The population is evolving, and natural selection is favoring one allele over another.
Step-by-step explanation:
According to Hardy-Weinberg equilibrium, the frequency (genetic variation) of population remains stable from one generation to the next generation.
The population will follow Hardy-Weinberg equilibrium if the population size is large, random mating, no natural selection , absence of mutation and gene flow.
If the population is evolving and natural selection favors an allele over another, this scenario will prevent that population to follow Hardy-Weinberg equilibrium.
Thus, the correct answer is option(A).