How did radio companies such as nbc™, whose actual broadcasts were free, make money?

The model that allowed NBC to make money is pretty much the standard model used nowadays. The broadcasters were selling airtime to sponsors so they could run advertisements during breaks of the shows that were being aired. The more popular the show, the more expensive the air time. And it was found out that it was a great deal for both the Radio and the advertisers.

most likely the answer would be a.) cupidity

definitions:

cupidity - greed for money or possessions

hydrophobia - extreme or irrational fear of water, especially as a symptom of rabies in humans

pathology - the science of the causes and effects of diseases, especially the branch of medicine that deals with the laboratory examination of samples of body tissue for diagnostic or forensic

patho -   relating to disease

yeah it is i have the dark knight