Answer:
b. sexual reproduction
Step-by-step explanation:
According to the Hardy-Weinberg theorem, allele and genotype frequencies of a population remain constant over generations when all the evolutionary forces are absent. To maintain Hardy-Weinberg equilibrium, the population should be large enough to prevent the change in allele frequencies by genetic drift and should exhibit random mating.
Random mating occurs when the individuals of a population do not have any mate preference for sexual reproduction. Therefore, a large population maintains the Hardy-Weinberg equilibrium when forces such as mutations, sexual selection, migration, etc. are not operative on the population and random mating sexual reproduction occurs.