Which two are natively included by the IEEE 802.1w standard?

Which two are natively included by the IEEE 802.1w standard? (Choose two.)

A.
Instances can control a selection of VLANs

B.
Load balancing

C.
Fast transition to forwarding state

D.
Backbone, uplink, and portfast (or equivalent)

E.
Root, loop, and BPDU guard (or equivalent)

Explanation:
802.1D Spanning Tree Protocol (STP) has a drawback of slow convergence. Cisco Catalyst
switches support three types of STPs, which are PVST+, rapid-PVST+ and MST. PVST+ is based
on IEEE802.1D standard and includes Cisco proprietary extensions such as BackboneFast,
UplinkFast, and PortFast. Rapid-PVST+ is based on IEEE 802.1w standard and has a faster

convergence than 802.1D. RSTP (IEEE 802.1w) natively includes most of the Cisco proprietary
enhancements to the 802.1D Spanning Tree, such as BackboneFast and UplinkFast. RapidPVST+ has these unique features:
Rapid-PVST uses RSTP to provide faster convergence. When any RSTP port receives legacy
802.1D BPDU, it falls back to legacy STP and the inherent fast convergence benefits of 802.1w
are lost when it interacts with legacy bridges.