Final answer:
Natural selection can lead to Hardy-Weinberg disequilibrium at nuclear loci through positive selection, which favors beneficial alleles and increases their frequency in the population. The correct option is C.
Step-by-step explanation:
Natural selection can cause Hardy-Weinberg (HW) disequilibrium at nuclear loci in the form of positive selection, which is option C. This process favors certain alleles that confer an adaptive advantage to organisms, thus increasing their representation in the gene pool over time.
Other processes that can lead to HW disequilibrium include genetic drift, gene flow, mutation, and nonrandom mating. However, in contrast to natural selection, genetic drift occurs randomly and is not necessarily adaptive.
The bottleneck and founder effects are examples of genetic drift that can reduce genetic diversity within a population, contrary to natural selection which can increase genetic diversity through positive selection for advantageous traits.