Which of the following is a true statement with respect to prototyping?

a. In the early stages of prototyping, system controls and exception handling may be sacrificed in the interests of simplicity, flexibility, and ease of use.

b. A prototype is a scaled-down, first-draft model that is quickly and inexpensively built and given to users to evaluate.

c. The first step in prototyping is to identify system requirements.

d. All of the statements are true.