The set of values of m for which x2+3xy+x+my−m has two factors, with integer coefficients, which are linear in x and y, is precisely:<spanclass=′latex−bold′>(A)</span>0,12,−12<spanclass=′latex−bold′>(B)</span>0,12<spanclass=′latex−bold′>(C)</span>12,−12<spanclass=′latex−bold′>(D)</span>12<spanclass=′latex−bold′>(E)</span>0