A Number of Different Genes Have Been Identified as Affecting

A number of different genes have been identified as affecting skin color and there are probably more as yet unidentified. Each of these genes likely has several regulatory protein factors affecting their expression, and those proteins are coded for by yet more genes. Thus there are many genes involved in determining skin color. A reasonable hypothesis about the geographic distribution of these genes is

A) different mutations affecting skin color are likely to be present in geographically different populations of humans.
B) humans living in areas with less UV radiation are likely to have many more mutations for skin color and therefore have a greater variation in skin color.
C) in any given geographic area, natural selection is likely to lead to a wide variation in skin color.