Critics of current TV programs expect that FCC (government) restrictions on popular shows, like children's adventure cartoons and R-rated movies, would force the TV stations to put on more responsible programming, like public-affairs shows and live productions of classical drama. But would they really want the government to get involved in broadcasting if they knew a little more about how the marketplace really works? Restrictions like this would result in milder, but still mindless, offerings. There would be more situation-comedies (sit-coms) about bewildered housewives, more coverage of small-town minor-league sports, and more talk shows about the private lives of so-called "celebrities."
The author of the passage assumes that
A. current TV programming is not irresponsible.
(A) is incorrect because the argument takes no position on whether current TV programming is "responsible" or not. The author is merely suggesting that a plan to make such programming "more responsible" would not have the desired effect. If anything, the author is implying that current programming is irresponsible, otherwise it would not need to be regulated.
B. FCC restrictions of TV shows will not necessarily be easy to enforce.
(B) is incorrect because the argument addresses regulation, not enforcement. In other words, the argument is concerned with what the rules are that might be made and what the effect of those rules might be, not whether it would be easy for the FCC to make sure those rules were followed.
C. those who want to restrict certain popular TV shows will not like their popular replacements.
(C) is correct. The argument is that if the FCC tries to encourage "more responsible" programming by restricting certain kinds of shows, the TV networks would not put on the kinds of shows the critics have in mind. They would keep putting on "mindless" shows like sit-coms and talk shows, just milder versions of them. More importantly, the author assumes that the critics would want the sort of high-minded cultural fare he suggests, and they wouldn't get it, which means they wouldn't like the new shows any more than the old ones.
D. the FCC should have no control over the TV industry, which is likely to serve the public better if it is not regulated.
(D) is incorrect because it is an opinion, and an opinion cannot be the underlying assumption of an argument. While it may be inferred that the author shares this opinion, the fact remains that an assumption is something that must be TRUE in order for the argument to be valid. An opinion cannot be true (or false).
E. The marketplace is the true test of whether or not a new program idea is worthwhile.
(E) is incorrect because it is also an opinion. The key phrase is "true test." The implication is that there is another test being proposed and this one is better, because it's "true." While it may, once again, be inferred that the author holds this opinion, the argument is not really about the superiority of the marketplace over government regulation. The reference to the marketplace in the stimulus is in the form of a rhetorical question, and a rhetorical question cannot be the argument.