Which of the Following Is an Argument of Propinquity Theory

Which of the following is an argument of propinquity theory?

A) Most people mate with those who are opposite to themselves.
B) People tend to fall in love within their own age, educational, and ethnic groups.
C) People are more likely to mate with the people with whom they frequently socialize.
D) Relationships last longer when people have significant differences between one another.