Let A = [(1, 0, 0), (2, 1, 0), (3, 2, 1)]. If U1, U2 and U3 are columns matrices satisfying
AU1 = [1, 0, 0], AU2 = [2, 3, 0], AU3 = [2, 3, 1] and U is 3 × 3 matrix whose columns are U1, U2 and U3 then
The sum of the elements of U-1 is
(A) -1
(B) 0
(C) 1
(D) 3