What technology in a Layer 2 access layer design helps utilize network bandwidth even on STP-blocked links?

The focus of this question is on maximizing network bandwidth availability in a Layer 2 access layer design, especially when dealing with STP (Spanning Tree Protocol) blocked links. The correct choice is based on the features offered by PVST+ (Per VLAN Spanning Tree Plus).

PVST+ allows for individual spanning tree instances for each VLAN, effectively enabling load balancing across multiple links that might otherwise be blocked by traditional STP mechanisms. When multiple VLANs are present, PVST+ facilitates the utilization of redundant links by allowing traffic for each VLAN to independently flow across different switch paths, rather than treating all VLANs as one single broadcast domain. This means that not all links need to be blocked, as PVST+ can selectively block and forward ports based on the active topology for each VLAN.

In contrast, other technologies listed have different functionalities or characteristics. EtherChannel allows for the bundling of multiple physical links into a single logical link, which increases bandwidth but does not specifically address the challenge of STP-blocked links for multiple VLANs independently. Rapid PVST+, while offering quicker convergence than PVST+, still relies on similar principles of VLAN-based spanning trees and does not inherently provide additional benefits in this context over PVST+. The original Spanning