oblem #2: The graph of z = f(x,y) is shown below. In each part, determine whether the given partial derivatives are positive, negative, or zero. (Note that the function is symmetric about 0 in both the x- and y- directions.) 15 10 5 Z. 0 -5 -10 2 0 -4 (a) f(-2,-2) and fxx(-2,-2) (b) fy(-2,-2) and fyy(-2,-2) (c) f(2,0) and fxx(2,0) (d) fy(2,0) and fyy(2,0) (A) positive, negative (B) negative, zero (C) zero, zero (D) zero, positive (E) positive, positive (F) positive zero (G) negative negative (H) negative positive (D) zero negative.