Let n(A) be the number of distinct real solutions of the equation x^{6} \minus{}2x^{4} \plus{}x^{2} \equal{}A. When A takes every value on real numbers, the set of values of n(A) is<spanclass=′latex−bold′>(A)</span>{0,1,2,3,4,5,6}<spanclass=′latex−bold′>(B)</span>{0,2,4,6}<spanclass=′latex−bold′>(C)</span>{0,3,4,6}<spanclass=′latex−bold′>(D)</span>{0,2,3,4,6}<spanclass=′latex−bold′>(E)</span>{0,2,3,4}