( 30 )有如下程序:#includeusing namespace std;class
A.A B.A{lilt k;protected:int n;void set C.K ( int k ) { this->k=k;}public:void set D.N ( int n ) { this->n=n;}};class E.B F.B: public }{/* 类体略 */};int main () { G.B H.n=1; //2x.set I.k=3; //4x .set J.K ( 4 ) ;return 0;}在标注号码的四条语句中正确的是 K.A ) 1 L.B ) 2 M.C ) 3 N.D ) 4