What action will be taken by a Cisco IOS router if a TCP packet, with the DF bit set, is larger than the egress interface MTU? 

Answer options:

A. Split the packet into two packets, so that neither packet exceeds the egress interface MTU, and forward them out.
B. Respond to the sender with an ICMP Type 3 , Code 4.
C. Respond to the sender with an ICMP Type 12, Code 2.
D. Transmit the packet unmodified.

B