Consider a triangular pyramid ABCD the position vector of whose angular points are A(3,0,1), B(−1,4,1), C(5,2,3) and D(0,−5,4) . Let G be the point of intersection of the medians of the △BCD . The length of the vector AG is
(1) 17
(2) 351
(3) 951
(4) 459