Which command would enable a VLAN on a switch port?

To enable a VLAN on a switch port, the command "SW1(config-if)# switchport access vlan vlan-number" is the correct choice. This command specifies that the switch port should operate as an access port and assigns it to a specific VLAN identified by the "vlan-number."

When configuring VLANs on a switch, it's essential to understand that a switch port can be an access port or a trunk port. Access ports are used to connect end devices to a single VLAN, whereas trunk ports can carry traffic from multiple VLANs. The command "switchport access vlan" is specifically designed for configuring an access port to associate it with a designated VLAN, making it crucial in VLAN implementations.

The other commands provided do not serve the intended purpose for enabling a VLAN on a switch port. They either do not exist in Cisco's command structure or are structured incorrectly for the context of the configuration.