A network consists of various remote sites that connect back to two main locations. The security administrator needs to block TELNET access into the network. Which of the following, by default, would be the BEST choice to accomplish this goal?

A.
Block port 23 on the L2 switch at each remote site.

B.
Block port 23 on the network firewall.

C.
Block port 25 on the L2 switch at each remote site.

D.
Block port 25 on the network firewall.