Suppose a Mutation Renders a Cell Incapable of Producing Functional

Suppose a mutation renders a cell incapable of producing functional P-TEFb. What effect would the mutation have on this cell?

A) RNA polymerases that are paused would not be able to resume elongation.
B) No transcription initiation complexes would be able to form.
C) No serine residues in the RNA polymerase CTD would be phosphorylated.
D) The cell would lose the ability to pause any of its transcription initiation complexes.