Quality means conformance to requirements - the degree to which the software meets its specified requirements. Option C is correct and aligns with the classic definition from software engineering (Crosby, 1979). Options A and B are slogans, not definitions. Option D is incomplete - software may work as designed but if design doesn't meet requirements, it's not quality. 'Conformance to requirements' is the standard, objective definition used in software quality assurance because it provides a measurable criterion: does the system do what was specified?