Appearance of facial hair in some people is an example of

The correct option is C Atavism
Atavism is the tendency to revert to ancestral type. In biology, an atavism is an evolutionary throwback, such as traits reappearing which had disappeared generations before. Appearance of facial hair in some people is an example of Atavism. Thus, option C is correct. Mongolism also referred as Down's syndrome, which is not related to appearance of facial hair. Thus, option A is wrong. Analogous organs are those that perform similar functions but have entirely different embryonic origins. An example of an analogous organ would be the arms and legs of tetrapods (amphibians, reptiles, birds and mammals) and the "legs" of insects. They are related to appearance of facial skin. Thus, option B is wrong.