In software testing, what is a Requirement Traceability Matrix (RTM) primarily used for?

Introduction / Context:
Requirement Traceability Matrix is a key document used in structured testing and quality assurance. As software systems become more complex, it is important to verify that all specified requirements have been tested and that no test case is unrelated to a business need. This question checks whether you understand the primary purpose of an RTM in the software testing life cycle.

Given Data / Assumptions:

• An RTM is a document or tool used in software projects.
• Projects usually have a set of documented requirements and a set of designed test cases.
• The organization wants to ensure full coverage of requirements by tests.
• We consider standard definitions used in quality assurance and testing practice.

Concept / Approach:
An RTM creates a bi directional link between requirements and test cases. Each requirement is given an identifier, and the matrix shows which test cases verify that requirement. This helps identify gaps where a requirement has no tests, as well as redundant tests that do not map to any requirement. The matrix supports coverage analysis, impact analysis when requirements change, and audits. Therefore, the correct option must mention mapping requirements to test cases and ensuring coverage.

Step-by-Step Solution:
Step 1 Recall that the RTM is built from the requirement specification and the test design documents. Step 2 Understand that each row or link in the RTM connects at least one requirement to one or more test cases. Step 3 Recognize that this mapping enables the team to check whether all requirements have corresponding tests. Step 4 Select the option that explicitly states that the RTM is used to map test cases to requirements and to ensure coverage.

Verification / Alternative check:
In many testing standards and templates, the RTM contains columns such as Requirement ID, Requirement Description, Test Case IDs, and Status. Managers and auditors use this document to verify that no requirement is left untested and that tests are justified by requirements. When a requirement changes, the RTM helps identify all affected test cases. These practical uses all depend on the core idea of requirement to test case mapping, confirming that this is the main purpose.

Why Other Options Are Wrong:
Storing source code version history is the role of a version control system, not the RTM. Managing network topology diagrams is a networking task, not a software testing activity. Calculating the execution time of each test case is part of performance measurement or test management tools, not the primary aim of an RTM. Replacing test plans and reports is also incorrect; the RTM complements these documents but does not eliminate them.

Common Pitfalls:
Teams sometimes treat the RTM as a formality and do not keep it updated, which reduces its usefulness. Another pitfall is creating an RTM that is too complex to maintain. A well designed RTM should remain simple enough to update easily, while still covering all requirements. Consistent use of the RTM improves transparency and helps demonstrate that the delivered product satisfies the specified needs.

Final Answer:
A Requirement Traceability Matrix is primarily used To map test cases to requirements and ensure that every requirement is covered by one or more tests.