The ping loopback hangs with no output. Which of the following is the most likely cause?()
A. The loopback interface is down and resolv.conf is configured.
B. The loopback is not in /etc/hosts and resolv.conf is configured.
C. The loopback interface is down and resolv.conf is not configured.
D. The loopback is not in /etc/hosts and resolv.conf is not configured.