The E7 Protein from Papillomavirus Stabilizes the Cellular P53 Protein

The E7 protein from papillomavirus stabilizes the cellular p53 protein, which leads to cell cycle arrest.Which of the following explains the mechanism by which p53 causes cell cycle arrest?

A) p53 activates transcription of p21, which blocks phosphorylation of pRb.
B) p53 binds to pRb and causes it to release the E2F transcription factor.
C) p53 binds directly to p21 and causes it to become degraded by the proteasome.
D) p53 binds to the viral E6 protein, which causes it to be degraded by the proteasome.
E) All of the above are correct.