Nokea
A theory is a set of concepts, definitions, relationships and assumptions that:
Correct Answer: A
Rationale: A theory in nursing, like Orem's Self-Care Deficit, comprises concepts (e.g., self-care), definitions (clarifying terms), relationships (how concepts interact), and assumptions (underlying beliefs), all to explain phenomena patterns or events like patient recovery. This explanatory role guides practice by providing a lens to understand health-related behaviors or outcomes. Formulating legislation is unrelated; theories inform policy indirectly but aren't legal tools. Measuring nursing functions might be a research outcome, not a theory's purpose, which is broader and conceptual. Reflecting the domain of nursing practice describes what theories encompass but not their active function explanation drives their utility. By explaining phenomena, theories offer nurses frameworks to predict, interpret, and address patient needs, making this the most accurate description of a theory's role in nursing science.