Which statement is true when ICMP echo and echo-reply are disabled on edge devices？（）

A.Pings are allowed only to specific devices.

B.CDP information is not exchanged.

C.Port scans can no longer be run.

D.Some network diagnostic data is lost.

E.Wireless devices need to be physically connected to the edge device.

F.OSPF routing needs the command ip ospf network non-broadcast enabled.