Which two of these statements regarding RSTP are correct? (Choose two.)

A.
RSTP cannot operate with PVST+.

B.
RSTP defines new port roles.

C.
RSTP defines no new port states.

D.
RSTP is a proprietary implementation of IEEE 802.1D STP.

E.
RSTP is compatible with the original IEEE 802.1D STP.

Explanation:
When network topology changes, rapid spanning tree protocol (IEEE802.1W, referred to as RSTP)
will speed up significantly the speed to re-calculate spanning tree. RSTP not only defines the role
of other ports: alternative port and backup port, but also defines status of 3 ports: discarding
status, learning status, forwarding status.
RSTP is 802.1D standard evolution, not revolution. It retains most of the parameters, and makes
no changes.