With a queuing model of a computer system, calibration is the process of:

a. Determining the size of the error in the values of the performance indices provided by the queuing model

b. Making the results of an open queuing model approximate the results of a closed queuing model

c. Reducing the size of the output errors by reducing or eliminating various forms of inaccuracies

d. Undertaking sensitivity analyses to determine the most important workload and system parameters