Solution

The Spiral model is an iterative development methodology that emphasizes continuous feedback from the customer and iterative refinement of the project. It combines elements of both design and prototyping, allowing for flexible development and the incorporation of customer feedback at multiple stages. a) Waterfall is a linear and sequential development methodology with little room for iterative feedback. c) The V-Model emphasizes verification and validation but is not iterative. d) Big Bang involves starting development without much planning or customer feedback and is not iterative. e) Incremental development adds functionality in parts but does not focus as heavily on iterative feedback as the Spiral model.