Which statement correctly describes the Cisco implementation of RSTP?

Which statement correctly describes the Cisco implementation of RSTP?

A.
PortFast, UplinkFast, and BackboneFast specific configurations are ignored in Rapid
PVST mode.

B.
RSTP is enabled globally and uses existing STP configuration.

C.
Root and alternative ports transition immediately to the forwarding state.

D.
Convergence is improved by using sub-second timers for the blocking, listening, learning,
and forwarding port states.