The Frequency of an Allele Is the Relative Number of That

The frequency of an allele is the relative number of that allele in the population, compared to other versions of the same gene. If an allele is being selected for in a population, would you expect the frequency to increase, decrease, or stay the same?

A) Increase, because the individuals with it will be doing better and reproducing more.
B) Decrease, because the individuals with it will be doing worse and reproducing less.
C) Stay the same because allele frequencies generally don't change.
D) It's impossible to predict because organisms change at random.
E) Increase, because individuals with it will be doing worse and reproducing less.