How many ways are there to divide a set with 6 elements into 3 disjoint subsets?<spanclass=′latex−bold′>(A)</span>90<spanclass=′latex−bold′>(B)</span>105<spanclass=′latex−bold′>(C)</span>120<spanclass=′latex−bold′>(D)</span>180<spanclass=′latex−bold′>(E)</span>243