which three are true about Cisco spanning-tree features?

Refer to the following descriptions, which three are true about Cisco spanning-tree features?
(Choose three.)

A.
RPVST+ converges faster than RSTP during a topology change.

B.
STP BPDUs are relayed by all non-root bridges and RSTP BPDUs are generated by each
bridge.

C.
RSTP can only achieve rapid transition to Forwarding on edge ports and on point-to-point links.

D.
RPVST+ and RSTP are both based upon the IEEE 802.1w specification.

Explanation:
PVST+ is per-VLAN spanning tree (which is the default for most cisco switches). It means that you
will run an spanning-tree instance per VLAN. This is useful when you need different layer 2
behaviors per VLAN, for example you can have different root bridge on different VLANs (so that
spanning tree does not have to run as a whole on the layer 2 domain, but can run a different
instance per- VLAN) RSTP is rapid STP. It is an enhancement to STP. RSTP does not work with
timers as regular STP (which takes up to 30-50 seconds to converge due to the transition to all its
states) Regular STP can use port-fast for ports not connected to other switches, but all ports

connected to other switches need to transition from blocking to listening, learning and finally
forwarding. RSTP optimizes this by using P2P links and taking up to only 2 seconds to converge.
RPVST+ Is a mix of PVST+ and RSTP. You have an instance of rapid STP running per VLAN.
Also, some use MST which is another variance of STP which can group several VLANs to be part
of a single MST region (and behave like RSTP inside that region). MST is useful because if you
have 1000 VLANs, normally you don’t need to have 1000 STP/RSTP instances! You can instead
have one instance with VLAN 1-500 and another instance with VLANs 501-1000 (just to give you
an example)