A company wants all IM chat via the internet to stop. A technician blocks IRC traffic with a traffic shaping device， yet IM chat remains useable. Which of the following should a technician do next？（）

A.Block both IRC and ICMP
B.Utilize SNMP to identify IM users
C.Contact the IM carrier to request the IM account be disabled
D.Change the shaping setting to allow minimal traffic to reduce port hopping