Answer:
The correct answer is option D, that is, small.
Step-by-step explanation:
A phenomenon in which the frequencies of alleles within a population get alter by chance alone as an outcome of sampling error from generation to generation is termed as genetic drift. It is a random process, which can result in huge modifications in populations over a short time duration.
This random drift is a result of repeated small population sizes, extreme decline in the size of the population known as founder events and bottlenecks where a novel population emerges from a small number of individuals. The genetic drift results in the fixation of genotypes or alleles in the populations.