What is the definition of natural selection?

I- Natural selection is the differential reproduction of genetic variants.
II- Natural selection is the process that results from the fulfillment of three conditions: phenotypic variation among individuals in a population, differential survival or reproduction associated with variation, and inheritance of variation.
III- Natural selection is the process that results from the fulfillment of two conditions: phenotypic variation among individuals in a population and differential survival or reproduction associated with variation.
a) Only I is correct.
b) Only II is correct.
c) Only III is correct.
d) I and II are correct.
e) II and III are correct.