Rather than focusing only on the nature of different types of people in their relationships to one another, georg simmel focused more on

I believe the answer is: Interaction between people

Simmel focused his life on researchers to study different type of social interaction that people do with one another. He consider things such as psychology, economics, culture, and sociology as crucial factors that motivate people to interact with one another.

the answer would be c. sediment buildup on continental slope

                                                                                -hope this -