Reviewing which of the following would BEST ensure that security controls are effective? 

Answer options:

A. Risk assessment policies
B. Return on security investment
C. Security metrics
D. User access rights

C

Reviewing security metrics provides senior management a snapshot view and trends of an organization`s security posture. Choice A is incorrect because reviewing risk assessment policies would not ensure that the controls are actually working. Choice B is incorrect because reviewing returns on security investments provides business justifications in implementing controls, but does not measure effectiveness of the control itself. Choice D is incorrect because reviewing user access rights is a joint responsibility of the data custodian and the data owner, and does not measure control effectiveness.