The Agile methodology is an iterative approach to software development that prioritizes customer satisfaction and flexibility. Its core principles, as defined in the Agile Manifesto, emphasize early and continuous delivery of functional software, close collaboration with customers, and the ability to welcome and adapt to changing requirements, even late in the development cycle. This contrasts with more rigid, sequential models. The focus is on delivering value and responding to change over strictly following a predefined plan, which directly aligns with the scenario described.

B. Spiral: The Spiral model is iterative, but its primary focus is on risk analysis and mitigation at each stage, not specifically on welcoming late-stage requirement changes.

C. Waterfall: This is a linear, sequential model where each phase must be completed before the next begins. It is known for its rigidity and difficulty in accommodating changes.

D. Lean: While sharing principles with Agile, Lean's primary focus is on eliminating waste and optimizing the development process to deliver value, rather than specifically on customer collaboration and changing requirements.

1. Beck

K.

Beedle

M.

van Bennekum

A.

Cockburn

A.

Cunningham

W.

Fowler

M.

Grenning

J.

Highsmith

J.

Hunt

A.

Jeffries

R.

Kern

J.

Marick

B.

Martin

R. C.

Mellor

S.

Schwaber

K.

Sutherland

J.

& Thomas

D. (2001). Manifesto for Agile Software Development. Agile Alliance. Retrieved from https://agilemanifesto.org/principles.html. The principles state

"Our highest priority is to satisfy the customer through early and continuous delivery of valuable software

" and "Welcome changing requirements

even late in development."

2. Boehm

B. (1988). A spiral model of software development and enhancement. Computer

21(5)

61-72. https://doi.org/10.1109/2.59. This foundational paper describes the Spiral model's emphasis on risk-driven iterations (see Figure 4

p. 65)

which is a different primary focus than that described in the question.

3. Royce

W. W. (1970). Managing the development of large software systems. Proceedings of IEEE WESCON

26(August)

1-9. This paper

often cited as the origin of the Waterfall model

describes a sequential

non-iterative process where feedback loops are treated as rework

highlighting its inflexibility to change.

4. Poppendieck

M.

& Poppendieck

T. (2003). Lean Software Development: An Agile Toolkit. Addison-Wesley Professional. The core principles of Lean software development are detailed as: Eliminate Waste

Amplify Learning

Decide as Late as Possible

Deliver as Fast as Possible

Empower the Team

Build Integrity In

and See the Whole. While related to Agile

the emphasis is on process optimization.