Answer: (A) Genetic drift
Step-by-step explanation:
The genetic drift is one of the process of random sampling in which the existent gene frequency are get changed in the organisms and it is also refers as the allelic effect.
According to the given question, In a small remote area the different types of people are living and in that area the "Blue skin" condition is highly incidence due to the variation in the hemoglobin structure.
So, the high frequency in the Blue skin in that specific area is one of the example of the genetic drift and the main role of the genetic drift is to determining the sampling error from the different generation gene.
Therefore, Option (A) is correct answer.