Answer: C)definition of empirical measures
Explanation: CSIRT(Computer Security Incident Response Team) is the team that is related with the taking the measurement according to the related incident of the security. The tasks that are performed by the team are detection of security error, dealing with it ,introducing ideas to resolve it etc.
Empirical measure is the measure that technique which has randomness. Random measures are the based on the possible methods that can be used for solving the security issue.Thus feedback of CSIRT is effective or not can be seen by the empirical technique.Thus, the correct option is option(c).