Rapid PVST+

B.

The correct answer to the question is B. PVRST+.

PVST+ (Per VLAN Spanning Tree Plus) is a Cisco proprietary protocol that supports a separate spanning-tree instance for each VLAN. PVST+ is based on the 802.1D standard and provides a faster convergence time by reducing the number of ports that need to transition to forwarding state during a topology change.

PVRST+ (Per VLAN Rapid Spanning Tree Plus) is an enhancement to PVST+ that supports the 802.1w standard, which has a faster convergence time than 802.1D. PVRST+ provides a separate spanning-tree instance for each VLAN, like PVST+, but uses the 802.1w standard to achieve faster convergence times.

CST (Common Spanning Tree) is the original IEEE 802.1D standard for spanning tree protocol, which is based on a single spanning-tree instance for the entire network. CST uses the same spanning-tree instance for all VLANs, which can result in slower convergence times for large networks.

MST (Multiple Spanning Tree) is an IEEE 802.1s standard that provides a way to map multiple VLANs onto a common spanning-tree instance. MST allows for the creation of multiple spanning-tree instances that can span across multiple VLANs, providing a way to optimize the use of network resources and achieve faster convergence times.

RST (Rapid Spanning Tree) is a Cisco proprietary protocol that is based on the 802.1D standard and provides faster convergence times than traditional STP. RST uses a similar method to PVST+ to reduce the number of ports that need to transition to forwarding state during a topology change, but does not support a separate spanning-tree instance for each VLAN.

In summary, PVRST+ is the spanning-tree mode that supports a separate spanning-tree instance for each VLAN and also supports the 802.1w standard for faster convergence times.