Refer to the exhibit. An administrator is attempting to configure a router by copying and pasting the commands that are shown in the exhibit. However, only one of the FastEthernet interfaces is coming up. What is the problem?
FastEthernet0/1 does not have a description.
There can be only one FastEthernet interface enabled on a router at one time.
The administrator did not exit to global configuration mode before configuring FastEthernet0/1.