Prototype is a ______________.

Answer: Option D

A prototype is a working model of a proposed (new) system that is developed to understand user requirements, evaluate design ideas, and obtain user feedback before the final system is built. It helps identify problems early and reduces the cost of making changes during development.

Why the other options are incorrect:

Option A: "Working model of existing system" is incorrect because a prototype is created for a proposed or new system, not an already existing system.

Option B: "Mini model of existing system" is also incorrect because a prototype does not represent an existing system. It represents the proposed solution that is under development.

Option C: "Mini model of processed system" is incorrect because "processed system" is not a standard term used in Management Information Systems (MIS) or Software Engineering to define a prototype.

Since none of the given options correctly define a prototype, the correct answer is Option D: None of the above.