Correct Answer: B

Explanation:
Rapid Spanning Tree Protocol (RSTP) is an enhancement of the original STP 802.1D protocol. The RSTP 802.1w protocol is an IEEE open implementation. Cisco has its own proprietary implementation of RSTP, that includes the benefits of its Per-VLAN spanning tree protocols, called Rapid-PVST+.
To activate the Rapid-PVST+ protocol:
switch(config)#spanning-tree mode rapid-pvst