Which of the following is not a software process model?

Answer: Glassboxing is not a software process model.

Reason: Glassboxing refers to glass-box (white-box) testing, which focuses on the internal structure of the code. Testing techniques describe how to verify software, not how to organize the development lifecycle, so glassboxing is not a software process model.

• Prototyping — A development approach that builds a working prototype early to clarify requirements and guide design; considered a software process/approach.

• Iterative — A process model where the product is developed through repeated cycles, allowing progressive refinement each iteration.

• Timeboxing — A time-limited approach (commonly spelled 'timeboxing') that fixes the duration of iterations; used as a development practice within process models (for example in agile).

• Glassboxing — Also called glass-box or white-box testing; a testing technique focused on internal code structure, not a model for organizing development activities.

Tip: To decide whether a term is a software process model, check whether it describes the sequence and organization of development activities (process model) versus a technique for testing or implementation detail (not a process model).