Final answer:
To enable the EtherChannel on SW2, the network administrator must use the command 'SW2(config-if-range)# channel-group 1 mode desirable'.
Step-by-step explanation:
To enable the EtherChannel on SW2, the network administrator must use the command SW2(config-if-range)# channel-group 1 mode desirable. To enable the EtherChannel on SW2, the network administrator must use the command 'SW2(config-if-range)# channel-group 1 mode desirable'.
This command sets the EtherChannel to actively negotiate with the other end of the link (SW1). The 'desirable' mode allows SW2 to actively try to form an EtherChannel, and if SW1 is also configured in an 'auto' mode, the EtherChannel will be created successfully.