Much . . . . . . . . been said in the news reports.

Answer: Option C

The given sentence states that the news reports have conveyed enough information and that it is uncountable.
Since it cannot be counted, the verb has to be in its singular and third-person form.
So, the verb 'has' will be used after much.
The other options - were, have, and was are not relevant and don't fit the given sentence.