What is the most likely cause of this?

While performing a ping sweep of a local subnet you receive an ICMP reply of Code 3/Type 13 for
all the pings you have sent out. What is the most likely cause of this?

A.
The firewall is dropping the packets

B.
An in-line IDS is dropping the packets

C.
A router is blocking ICMP

D.
The host does not respond to ICMP packets