Concept:Mental health is best understood as an idea or notion rather than a fixed theory, model, or standard.Explanation:Mental health covers emotional, psychological, and social well-being. It influences how we think, feel, and act. It also affects how we handle stress, relate to others, and make choices. Unlike a theory or model, mental health is a broad concept that changes across cultures and individuals. It is not the same as mental illness. A person can have poor mental health without having a diagnosed illness. Since it is an abstract idea shaped by many factors, it is correctly termed a concept.Answer:C. concept