设有如下代码:interface IFace{}class CFace implements IFace{}class Base{}public class ObRef extends Base{ public static void main(String argv[]){ ObRef obj = new ObRef(); Base b = new Base(); Object obj1 = new Object(); IFace obj2 = new CFace(); //Here }}则在//Here 处插入( )代码将不出现编译和运行错误。 A. obj1=obj2; B. b=obj; C. obj=b; D. obj1=b;