Mikki and Jeremiah both have PhDs. They got married in their late thirties, after they finished their educations. While their marriage hasn't been perfect and they have had some fights over money and other issues, they have worked things out and stayed married. In the context of factors that affect marriage and divorce in the United States, which of the following most likely influenced their marriage?
a. Micro-level factors
b. Societal factors
c. Demographic variables
d. Macro-level factors
e. Individual factors