Xavier, Yvonne, and Zelda each try independently to solve a problem. If their individual probabilities for success are 1/4,1/2, and 5/8 , respectively, what is the probability that Xavier and Yvonne, but not Zelda, will solve the problem ?
(A) 11/8
(B) 7/8
(C) 9/64
(D) 5/64
(E) 3/64
(A) 11/8
(B) 7/8
(C) 9/64
(D) 5/64
(E) 3/64
