Which of the following examples of natural selection in action would tend to increase the genetic variation in the population?

Natural selection simultaneously selects against heavy field mice (they starve during winter) and light field mice (they freeze during winter).

Natural selection causes dragonflies to evolve longer tails.

Natural selection acts on beak size in finches such that those individuals able to eat small, soft seeds survive through the winter.

Alpine sky-pilots evolve large flowers above the timberline and small flowers below the timberline.

Natural selection occurs when organisms or species with certain genotypes are more likely to survive and reproduce, compared to individuals with other genotypes, and thus to pass on their alleles to the next generation.
Alpine skypilots evolve large flowers above the timberline and small flowers below the timberline. This is an example of disruptive selection, which increases genetic variation.
Longer tails in dragonflies and finches for a particular beak size are examples of directional selection, which decreases genetic variation.
Natural selection against heavy and light field mice is an example of stabilizing selection, which reduces genetic variation