GMAT Sentence Correction (SC) | Which of the following best completes the passage below? the

Thanks for your reply but I still can't really understand why the answer should be C & not D because the argument clearly states that coverage on "who's winning" isn't goodat the expense of issues and candidates position; otherwise media could probably cover "who's winning" but not at the expense of "issues and candidates' position"
“Who’s winning?”at the expense of substantive coverage of the issues and the candidates’ positions on them

Experts, could