Final answer:
The four techniques discussed for verification and validation are testing, inspection, review, and walkthrough.
Step-by-step explanation:
The four techniques discussed for verification and validation are:
1) Testing: This involves executing the software or system to check if it meets the specified requirements and objectives. It helps identify any errors or defects.
2) Inspection: This technique involves manually examining the software or system design, code, and documents to identify errors, inconsistencies, and deficiencies.
3) Review: This technique involves a structured examination of the software or system by a group of people to evaluate its quality and compliance with requirements.
4) Walkthrough: This technique involves the author of the software or system presenting it to others to gather feedback and identify potential issues.