An extranet server should be placed:

A.
outside the firewall.

B.
on the firewall server.

C.
on a screened subnet.

D.
on the external router.

Explanation:

An extranet server should be placed on a screened subnet, which is a demilitarized zone (DMZ).
Placing it on the Internet side of the firewall would leave it defenseless. The same would be true of
placing it on the external router, although this would not be possible. Since firewalls should be
installed on hardened servers with minimal services enabled, it would be inappropriate to store the
extranet on the same physical device.