If w is one of the imaginary roots of the equation x3=1, then the product (1−w+w2)(1+w−w2) is equal to<spanclass=′latex−bold′>(A)</span>4<spanclass=′latex−bold′>(B)</span>w<spanclass=′latex−bold′>(C)</span>2<spanclass=′latex−bold′>(D)</span>w2<spanclass=′latex−bold′>(E)</span>1