Treatment of influenza infected cells with actinomycin D and a-amanitin, which inhibit the activity of the cellular RNA polymerase II, shut down the synthesis of viral mRNAs.Which of the following describes the mechanism of this inhibition?

A) The viral RNA-dependent RNA polymerase is also inhibited by these compounds.
B) The virus needs a supply of nuclear pre-mRNAs to snatch caps from.
C) These inhibitors reduce the supply of nucleotides for transcription.
D) The cellular RNA polymerase synthesizes the viral mRNAs.
E) This leads to the degradation of the viral RNA genome segments.