Step 1: Identify Key Factors for Natural Selection.
For natural selection to act on a trait, it must confer a fitness advantage, vary among individuals, and be heritable.
Step 2: Analyze Each Condition.
(A) If increased nectar production leads to greater fruit set and more offspring, it provides a reproductive advantage, a key component of natural selection.
(B) Variation in nectar production across individuals allows natural selection to favor those with optimal nectar production.
(D) Heritability of nectar production ensures that beneficial traits are passed to the next generation, allowing natural selection to act over successive generations.