Jamie and Kennedy date and eventually marry. Both of them are of the same race, were raised Southern Baptist, and come from middle-class families. What does this exemplify

Similarity-Attraction Theory.

Explanation:

The theory of similarity-attraction suggests that people are most likely to be attracted to those who have shared interests. This body has been researched by many researchers and scholars such as Ellen Berscheid, Donn Byrne, etc.

In 1971, Byrnne came up with a theory of 'Law of attraction' which was further studied by many scholars and researchers.

The theory of similarity-attraction suggests that people who share similarities in religion, socio-economic status, social habits, etc are most attracted to each.

In the given case, Jamie and Kennedy share the same race, religion, and socio-economic status. Thus their relationship exemplify the similarity-attraction theory.