If a,b,c are non-zero real numbers such that ca+b−c=ba−b+c=a−a+b+c, and x=abc(a+b)(b+c)(c+a), and x<0, then x equals<spanclass=′latex−bold′>(A)</span>−1<spanclass=′latex−bold′>(B)</span>−2<spanclass=′latex−bold′>(C)</span>−4<spanclass=′latex−bold′>(D)</span>−6<spanclass=′latex−bold′>(E)</span>−8