Forward-time is the Rapid PVST+/STP timer that controls the listening and learning periods before a port is allowed to forward user traffic. The command spanning-tree vlan 1 forward-time 20 sets that timer for VLAN
1 to 20 seconds. The other commands tune different STP values: max-age controls how long bridge protocol information is retained, hello-time controls BPDU transmission frequency, and priority affects root-bridge election. For CCNA 200-301 v1.1 Network Access, the key distinction is that a port must listen, then learn MAC addresses, then forward. Cisco Catalyst documentation describes forward time as the value that determines how long the listening and learning states last before forwarding begins. Because the question specifically says the switch "listens and learns for a specific time period," the only command that directly matches that behavior is the VLAN forward-time command. Reference: Cisco Catalyst Spanning Tree configuration guidance; CCNA 200-301 v1.1 Network Access objectives.