Which of the following statements best describes why an evaluator must validate the results of an evaluation performed using analytical models?

a) Systems are often too complex to model accurately, so the results of analytical models are often erroneous.
b) The evaluator needs the results of other performance evaluations to build the model in the first place.
c) Analytical models are useful in the development process, but many consumers distrust or do not understand analytical models. A vendor must validate the results of an analytical model before presenting the results to potential customers.
d) In general, it is a good idea to use multiple techniques to test a system. Additionally, because an evaluator often must make simplifying assumptions to model complex systems, other evaluations should be done to verify that these assumptions are valid.

d) In general, it is a good idea to use multiple techniques to test a system. Additionally, because an evaluator often must make simplifying assumptions to model complex systems, other evaluations should be done to verify that these assumptions are valid.