Which white-box testing technique intentionally introduces small faults ('mutants') into source code to evaluate test suite completeness?
Option A is correct. Mutation Testing modifies code statements slightly to create 'mutants'. If the existing test suite detects and fails the mutant, the mutant is 'killed'.
Which category of software maintenance accounts for over 50% of all maintenance effort, focusing on enhancing user features and performance?
Option A is correct. Perfective Maintenance modifies software to improve performance, maintainability, or add new features requested by users, accounting for over 50% of total maintenance.
Which category of software maintenance modifies software to keep it operational when operating system environments or hardware hardware platforms change?
Option C is correct. Adaptive Maintenance adapts software to changes in its external operational environment (e.g., OS upgrades, hardware changes, or database migrations).
Which category of software maintenance involves fixing bugs, errors, and defects discovered during actual system execution?
Option A is correct. Corrective Maintenance diagnoses and fixes reported errors, logic flaws, and operational bugs.
What is the process of modifying internal source code structure without altering its external functional behavior called?
Option D is correct. Code Refactoring improves internal code structure, readability, and maintainability while leaving external behavior unchanged.