The author does not attribute C to Marcuse. Rather, C is the author's response to Marcuse's concept of real needs vs. false needs. Marcuse did see a distinction between these things, but it is the author who believes this distinction is problematic.
See line 26: "Unfortunately, the distinction between real and false needs upon which this critique depends is extremely problematic." The critique in question belongs to Marcuse, and it depends on the concept of false needs. Marcuse did not believe it is impossible to draw such a distinction.
