The most consistent factor involved in forming relationships and selecting mates is

A) personal chemistry.
B) the unique individual characteristics of the individuals involved.
C) the tendency to choose mates who are similar in class, race, ethnicity, and age.
D) the desire to find a mate who comes from a radically different background.

Research has consistently shown that people tend to choose mates who are similar in class, race, ethnicity, and age. This is known as homophily or assortative mating. Personal chemistry and unique individual characteristics can certainly play a role in relationship formation, but they are not as consistently influential as shared social and demographic characteristics. The desire to find a mate from a radically different background is relatively uncommon and may indicate a preference for novelty or adventure rather than a stable long-term relationship.