Answer:
A. Bees bringing pollen from the flower of one plant to the flower of another plant.
Step-by-step explanation:
Genetic diversity in organisms is enhanced by the process of sexual reproduction due to the meiotic process that the participant organisms undergo to produce gametes. A process unique to meiosis called CROSSING OVER ensures that the alleles of genes are recombined in the GAMETE or sex cells.
According to this question, POLLINATION, which is the transfer of pollen from a male flower to a female one, will lead to sexual reproduction via fertilization. However, a cross-pollination, which requires a pollinator like the bees in this question will ensure the most genetic diversity among the offsprings.