During which lifecycle phase is formal requirements analysis primarily performed and documented?

Introduction / Context:
Traditional system lifecycles distinguish discovery and definition activities from design and construction. Requirements analysis is the rigorous activity of eliciting, analyzing, modeling, and validating what the system must do and under what constraints, producing artifacts that guide subsequent phases.

Given Data / Assumptions:

• The project begins with recognizing a business problem or opportunity.
• A structured lifecycle is being followed (e.g., investigation → analysis → design → implementation).
• Deliverables of analysis become inputs to design.

Concept / Approach:
In the system analysis phase, analysts refine the problem statement, develop models such as data flow diagrams, entity definitions, and use cases, and produce a requirements specification. Design transforms these requirements into technical solutions; development implements them; investigation precedes analysis and confirms feasibility to proceed.

Step-by-Step Solution:

Verification / Alternative check:
Cross-check deliverables: if the artifact defines what and why (not how), it belongs to analysis; if it defines how (architecture, components), it belongs to design.

Why Other Options Are Wrong:

Common Pitfalls:
Mixing solution decisions into analysis prematurely can bias vendors and constrain innovation; conversely, vague analysis leads to scope creep later.

Final Answer:
System analysis phase.