A population will not exist in Hardy-Weinberg equilibrium if

The correct option is C Individuals mate selectively.
The HardyWeinberg principle, also known as the HardyWeinberg equilibrium, model, theorem, or law, states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences. These influences include mate choice, mutation, selection, genetic drift, gene flow and meiotic drive. Because one or more of these influences are typically present in real populations, the HardyWeinberg principle describes an ideal condition against which the effects of these influences can be analyzed.