Refer to the exhibit.

UplinkFast is the correct spanning-tree feature for faster convergence after an uplink failure in a classic STP access-layer design. UplinkFast is designed for access switches that have redundant uplinks toward the distribution layer. When the primary root port fails, UplinkFast allows an alternate blocked uplink to transition rapidly to forwarding, reducing the outage compared with standard 802.1D timer-based convergence. PortFast is used on edge ports connected to end hosts, not on switch-to-switch uplinks. Loop Guard protects against unidirectional failures or missing BPDUs on non-designated ports, but it does not accelerate recovery from an access uplink failure. BackboneFast helps when an indirect link failure is detected elsewhere in the topology, but the described failure is directly between SW1 and SW2. The design objective is the fastest possible convergence during that direct uplink loss, which matches UplinkFast in a traditional STP environment. Reference topics: Spanning Tree Protocol, UplinkFast, access-layer redundancy, root port failover, Layer 2 convergence.