What IPS risk rating allows the user to assign a risk weighting based on the relative
importance of the system involved?

A.
Signature Fidelity Rating

B.
Mack Relevancy Rating

C.
Target Value Rating

D.
Alert Severity Rating

Explanation:
the TVR is a user-defined value that represents the user’s perceived value of the target
host. This allows the user to increase the risk of an event associated with a critical system and to de-emphasize the risk of an event on a low-value target.
http://www.cisco.com/c/en/us/products/collateral/security/ips-4200-series-sensors/prod_white_paper0900aecd80191021.html