Which of the following is NOT a valid use case for useMemo?
Memoizing event handler functions is not a valid use case for useMemo - you should use useCallback for this purpose instead. useMemo is designed to memoize computed values, not functions. While technically you could use useMemo to memoize a function by returning the function, the proper hook for this purpose is useCallback, which has a more declarative API specifically designed for memoizing functions.