The correct answer is option letter B (Whether you like his brand of comedy or not, Jon Stewart probably will not disappear from our TV screens anytime soon.). As regards effectiveness, the sentence in option letter B is the only sentence that express the idea correctly. By using the construction “whether … or not”, the meaning intended is “it’s not important if” or “it doesn’t matter if”. In this case, the speaker tries to explain that it does not matter if someone likes Jon Stewart’s brand of comedy or not; he will continue appearing on TV screens, he will not disappear. The rest of the options use the Introductory It (A) and the Existential “There” (C) constructions and these constructions do not contribute to the effectiveness of the whole sentence, since they make the sentence wordier and less fluent.