The function f(x) = x2 undergoes a transformation. Which quadratic function represents a vertical stretch and a shift up of 3 units? A) f(x) = 2x2 + 3 B) f(x) = x2 − 3 C) f(x) = 1 5 x2 + 3 D) f(x) = 0. 5x2 − 3