I got this wrong on my PT. I chose answer B, because I misinterpreted it to be something along the lines of "Assumes that the media gives equal time to the individual opinions presented."
It doesn't say this at all as the answer choice just makes a blanket statement about the wide range of opinions in general.
Answer choice C is the correct answer. Here's the diagram:
If the media purveyed--------It would be true that the power of
range of opinions -------->the media to impose opinions is
narrower than found-----------too great.
among consumers
The media does not------------------It is not true that the power
purvey range of opinions -------> of the media to impose
narrower than found among--------- opinions is too great
consumers
So you can see that it sets up a conditional statement in the premise, and then makes a conclusion that is a mistaken negation of that conditional statement.