The correct option is A refers to the random change in the gene frequency
Genetic drift is the random change in the gene frequency by a chance event. Genetic drift may occur in populations of different sizes be it large or small, however, its effects are more prominent in small populations.
A smaller population already has a reduced gene pool. Loss of alleles from a smaller population will more profoundly be noticeable within a less time duration.
This leads to a change in the allele frequencies randomly.
Since genetic drift is a random change in the allele frequency, it can be a change in the dominant or recessive or both alleles. It need not necessarily be a change in only the recessive alleles.
Inbreeding is the mating of individuals which are closely related through common ancestors.