What is a virtual firewall?()
A.another name for a firewall deployed in routed mode
B.another name for a firewall deployed in transparent mode
C.a separation of multiple firewall security contexts on a single firewall
D.a firewall that, when deployed in routed mode, can support up to 1000 VLANs per context
E.a firewall that has multiple contexts, all of which share the same policies (such as NAT and ACLs)