Assuming that the necessary derivatives of f(x,y,z) are defined, how are Dif, Dif, and Dif related to fx, f, and f- ? Give reasons for your answer. Choose the correct answer below. O A. D,f, D, f, and Def are not related to f,, f, and fz. O B. Dif, D, f, and Dif represent the rate of change in the same direction as f,, f, and f, respectively, because directional vectors and gradient vectors have the same direction. O C. Dif, D, f, and Dif are equal to fo, for and f, respectively, because when u = i, the directional derivative at Po is fx evaluated at that point, when u = j, the directional derivative at Po is fy evaluated at that point, when u = k, the directional derivative at Po is f, evaluated at that point