In software quality assurance theory, what is the difference between verification and validation when ensuring that a product meets expectations?

Introduction / Context:
Verification and validation are classic quality assurance concepts that appear in almost every testing interview. Many organisations even use these words in their process documents and audit checklists. Understanding the difference helps testers explain where different types of activities, such as reviews and user acceptance testing, fit within the software development life cycle.

Given Data / Assumptions:
- Verification is associated with checking artefacts against specifications.
- Validation is associated with checking the product against user needs and real usage conditions.
- Both are important and complementary; neither alone is sufficient for high quality software.
- The question is purely conceptual with no numeric computation.

Concept / Approach:
A common way to remember these terms is the phrases “Are we building the product right?” for verification and “Are we building the right product?” for validation. Verification activities include reviews, walkthroughs, inspections, static analysis and various forms of testing that confirm conformance with written requirements and design. Validation activities include user acceptance testing, beta testing and field trials that focus on whether the software actually solves the customer problem and fits real workflows.

Step-by-Step Solution:
Step 1: Recall the standard definitions that differentiate building the product right versus building the right product. Step 2: Examine each option to see which one uses this language or meaning. Step 3: Option a clearly states that verification checks the product against specified requirements and design, which fits the idea of building it correctly. Step 4: Option a also states that validation checks whether the product meets user needs and intended use, which matches the idea of building the right product. Step 5: Therefore, option a is the correct answer.

Verification / Alternative check:
To double check, consider where user acceptance testing fits. It is clearly focused on whether users are happy with how the system behaves in realistic scenarios, so it counts as validation. In contrast, reviewing a design document against the requirement specification is verification. Option a supports this mapping, confirming its correctness.

Why Other Options Are Wrong:
Option b incorrectly restricts verification and validation to specific testing types and confuses unit and performance testing. Option c is wrong because the two terms exist precisely to highlight different viewpoints. Option d reverses the emphasis and creates confusion between user satisfaction and coding standards, which does not match accepted definitions.

Common Pitfalls:
A frequent mistake is assuming that successful system testing automatically guarantees validation. In reality, a system might meet all documented requirements yet still fail to satisfy users if those requirements were incomplete or misinterpreted. Another pitfall is to treat verification activities such as reviews as optional, which often allows defects to propagate into later stages.

Final Answer:
Verification checks whether the product is built correctly against specified requirements and design, while validation checks whether the right product has been built by confirming that it meets user needs and intended use in the real world.