If a,b,c, and d are non-zero numbers such that c and d are the solutions of x2+ax+b=0 and a and b are the solutions of x2+cx+d=0, then a+b+c+d equals<spanclass=′latex−bold′>(A)</span>0<spanclass=′latex−bold′>(B)</span>−2<spanclass=′latex−bold′>(C)</span>2<spanclass=′latex−bold′>(D)</span>4<spanclass=′latex−bold′>(E)</span>(−1+5)/2