The network administrator wants to enable an EtherChannel between two switches in "on" mode. The administrator connects the cables and enables the interfaces, but while configuring the EtherChannel in the first switch, a spanning-tree loop was detected. Which two of these procedures can avoid this problem? (Choose two.)

A.
Configure the EtherChannel as "desirable" first.

B.
Assign all interfaces to the same VLAN.

C.
Disable PortFast on the interfaces in the EtherChannels.

D.
Disable all interfaces first.

E.
Fast Ethernet and Gigabit Ethernet ports cannot be assigned to the same EtherChannel.

F.
Fix cabling problems.