Consider equations of the form x2+bx+c=0. How many such equations have real roots and have coefficients b and c selected from the set of integers {1,2,3,4,5,6}?<spanclass=′latex−bold′>(A)</span>20<spanclass=′latex−bold′>(B)</span>19<spanclass=′latex−bold′>(C)</span>18<spanclass=′latex−bold′>(D)</span>17<spanclass=′latex−bold′>(E)</span>16