单项选择题

A.p->prior=q;q->next=p;p->prior->next=q;q->prior=q;
B.p->prior=q;p->prior->next=q;q->next=p;q->prior=p->prior;
C.q->next=p;q->prior=p->prior;p->Prior->next=q;p->prior=q;
D.q->prior=p->prior;q->next=q;p->prior=q;p->prior=q;