Answer: (ii) Spiral Model

The Spiral model (Boehm) is the SDLC model that emphasizes iterative development — the software evolves through repeated loops, each pass refining the product and adding functionality while incorporating risk analysis, development, testing, and customer evaluation at every cycle.

Why the others are wrong:

• (i) Waterfall model — a purely linear/sequential model, not iterative.
• (iii) Code-and-Fix model — a simplistic informal "code then fix problems" approach, not a structured iterative model.
• (iv) Prototyping — although prototypes are built in iterations, the classic model that emphasizes iterative development combined with risk analysis is the Spiral model; prototyping is focused on requirement clarification rather than full iterative development.

So the model that emphasizes iterative development is the Spiral Model — option (ii).