Which knowledge area focuses on ensuring that all project work is completed as planned?

Correct answer: Project Scope Management

Option C is correct because Project Scope Management is the knowledge area responsible for defining, validating, and controlling what is and is not included in the project, ensuring all required work, and only the required work, is completed as planned. Option A is wrong because Project Resource Management focuses on identifying, acquiring, and managing the people and physical resources needed to complete the project. Option B is wrong because Project Schedule Management (historically called Time Management) deals with planning and controlling the project timeline, not defining what work must be done. Option D is wrong because Project Quality Management ensures deliverables meet defined quality standards and requirements, which is a distinct concern from defining the totality of project work.