Final answer:
Prototyping is a key step in system design that allows for iterative model creation, evolution, and modification to meet end-user needs, contrasting with a sequential design process and forming part of the spiral design process.
Step-by-step explanation:
The approach of prototyping in system design allows for the creation and iteration of a system model. This model can be continuously evolved and modified based on better understanding of end-user requirements through a series of design processes. Such processes include prototyping, testing, and refinement. In contrast to a sequential design process, the prototyping approach is part of a spiral design process. The iterative nature of prototyping means that the prototype is repeatedly evaluated and improved upon. Weaknesses identified during testing phases lead to design refinements, driving the development towards a system that meets user needs and system requirements.
Thus, the correct answer to the student's question is: a. this approach permits formation of a model of the new system that can be evolved and modified in an iterative fashion as systems analysts and designers better know end users' needs.