以下哪些方式能获得Graphics对象obj？
选项：

A:Graphics obj = 窗体或控件名.CreateGraphics();;
B:private void 窗体或控件名_Paint(object sender, PaintEventArgs e){ Graphics obj = e. Graphics;};
C:Bitmap map = new Bitmap(宽,高);Graphics obj = Graphics.FromImage(map);obj.DrawImage(map, x坐标, y坐标);;
D:Graphics obj = new Graphics(宽,高);