Debugging is the process of finding, analyzing and removing the causes of failures in software. Debugging is not considered part of testing, but rather a development activity that can involve testing. Debugging is not intended to find as many defects as possible, but rather to fix the specific failure that was observed. Debugging is usually performed by developers, not by test engineers. Verified Reference:A Study Guide to the ISTQB Foundation Level 2018 Syllabus - Springer, Chapter 1, page 6.

Use case testing is a technique that helps identify test cases that exercise the whole system on a transaction by transaction basis from start to finish. Use cases are descriptions of how users interact with the system to achieve a specific goal. Use case testing is not focused on data flow, but rather on process flow. Use case testing can be performed by professional testers, customers or end users, depending on the context. Use case testing does not require the test cases to be designed by customers or end users, but rather by anyone who has access to the use case specifications. Verified Reference:A Study Guide to the ISTQB Foundation Level 2018 Syllabus - Springer, Chapter 4, page 36.

A technical review is a type of formal review that involves a team of technical experts who evaluate a software product against a set of predefined quality criteria. A technical review is suitable for ensuring high quality and technical correctness of complex or critical software components, such as algorithms, architectures or designs. A technical review is not a walkthrough, which is an informal review led by the author of the work product. A technical review is not an informal review, which is a review that does not follow a defined process and has no formal entry or exit criteria. A technical review is not a management review, which is a type of formal review that focuses on business aspects and project progress. Verified Reference:A Study Guide to the ISTQB Foundation Level 2018 Syllabus - Springer, Chapter 3, page 29-30.

The extent of testing required for a software product depends on various factors, such as the level of risk, the budget, and the time available. The level of risk reflects the potential impact of failures on the stakeholders and the environment. The budget determines how much resources can be allocated for testing. The time available defines the schedule and deadlines for testing activities. The particular tester involved in testing is not a deciding factor for the extent of testing required, as testing should be based on objective criteria and not on personal preferences or abilities. Verified Reference: [A Study Guide to the ISTQB Foundation Level 2018 Syllabus - Springer], Chapter 2, page 14-15.

The correct answer can be derived by applying the given rules to each case:

A is ST certified and has 12 years of testing experience, which is more than 10 years. Therefore, A does not match any of the rules and the result is unknown.

B is not ST certified and has 7 years of testing experience, which is between 5 and 10 years. Therefore, B matches rule 3 and the result is limited access.

C is not ST certified and has 3 years of testing experience, which is less than 5 years. Therefore, C does not match any of the rules and the result is unknown. Verified Reference: This question does not require any external references, as it is based on logical reasoning.