Let n be the number of real values of p for which the roots of
x2−px+p=0
are equal. Then n equals:<spanclass=′latex−bold′>(A)</span>0<spanclass=′latex−bold′>(B)</span>1<spanclass=′latex−bold′>(C)</span>2<spanclass=′latex−bold′>(D)</span>a finite number greater than 2<spanclass=′latex−bold′>(E)</span>an infinitely large number