Refer to the exhibit.

HostA cannot ping HostB. Assuming routing is properly configured, what could be the cause of this problem?

A.	HostA is not on the same subnet as its default gateway.
B.	The address of SwitchA is a subnet address.
C.	The Fa0/0 interface on RouterA is on a subnet that can't be used.
D.	The serial interfaces of the routers are not on the same subnet.
E.	The Fa0/0 interface on RouterB is using a broadcast address.