In sociology, Marx's theories are used to study society through economic systems. ... Conflict theory has been used to examine several aspects of society that are built upon class conflict, which Marx argued were designed to protect the wealthy, not society as a whole.
B. Think about the way the two chunks are said. The second part is more of an added thought, scoffed out. Dashes are perfectly fine where they are. C is definitely incorrect because the second sentence is just a dependent clause. A just doesn't make much sense. Dashes are pauses, breaks in what a person says. They can signal emotional changes, too.
