Refer to the exhibit.HostA cannot ping HostB.Assuming routing is properly configured,what could be the cause of this problem?（）
- AHostA is not on the same subnet as its default gateway
- BThe address of SwitchA is a subnet address
- CThe Fa0/0 interface on RouterA is on a subnet that cannot be used
- DThe serial interfaces of the routers are not on the same subnet
- EThe Fa0/0 interface on RouterB is using a broadcast addre