15.如果圆x2+y2+Dx+Ey+F=0经过原点,而且与x轴只有一个交点,那么( )
0 233642 233650 233656 233660 233666 233668 233672 233678 233680 233686 233692 233696 233698 233702 233708 233710 233716 233720 233722 233726 233728 233732 233734 233736 233737 233738 233740 233741 233742 233744 233746 233750 233752 233756 233758 233762 233768 233770 233776 233780 233782 233786 233792 233798 233800 233806 233810 233812 233818 233822 233828 233836 266669
| A. | F=0,D≠0,E≠0 | B. | E=F=0,D≠0 | C. | D=F=0,E≠0 | D. | D=E=0,F≠0 |