Which feature does MST support?

The correct choice highlights that Multiple Spanning Tree (MST) allows for Multiple VLANs to be mapped to a single instance. This feature is one of the key advantages of MST, as it enables efficient use of network resources by reducing the number of active spanning tree instances.

In a typical spanning tree configuration, each VLAN would have its own instance, leading to potentially many instances if numerous VLANs are in play. However, with MST, multiple VLANs can share the same spanning tree instance. This not only simplifies the configuration but also decreases the overhead on the network by controlling the number of spanning tree computations.

This design choice is particularly beneficial in larger networks where scalability and management are critical considerations. It allows for better load balancing and traffic engineering across the links of the network, optimizing overall performance.

Given this context, the other options do not align with the MST capabilities: mapping a single VLAN to a single instance is characteristic of earlier spanning tree protocols, and implying no support for VLANs directly contradicts MST's functionality.