Let f(x, y)equals=x squared minus xy plus y squared minus yx2−xy+y2−y. find the directions u and the values of upper d subscript bold uduf(1,minus−1) for which the following is true. a. upper d subscript bold uduf(1,minus−1) is largest b. upper d subscript bold uduf(1,minus−1) is smallest c. upper d subscript bold uduf(1,minus−1)equals=0 d. upper d subscript bold uduf(1,minus−1)equals=4 e. upper d subscript bold uduf(1,minus−1)equals=minus−3