Let f be a function that is differentiable at a. Which of the following is/are correct statements of the definition of f (a), the derivative of f at a? f (ac) - f(a) x - a lim flat h) - f(h) h-0 h lim f ( 2) - f (a ) x - a flat h) - f(a) lim h-0 h flath) - f(a) h f (ac) - f(a) lim ac - a