Which of the following methods is called once in a StatefulWidget's lifecycle?

Step 1: Identify methods unique to React core library. setState() is a method for class-based components in React. useState() is a hook exclusive to functional components in React. dispatch() is commonly associated with Redux library (external to React core), though similar in useReducer hook. Assuming D is useEffect(), which is a React hook. Step 2: Determine exclusivity. setState() and useState() are part of React core. dispatch() is not a standalone React core method (Redux-specific convention). useEffect() is React core. Step 3: Select the method only in React core (typical quiz intent for hooks). The answer is useState(), option B. B