在循环双链表的p所指的结点之前插入s所指结点的操作是 ( )
A. p->prior = s;s->next = p;p->prior->next = s;s->prior = p->prior;
B. p->prior = s;p->prior->next = s;s->next = p;s->prior = p->prior;
C. s->next = p;s->prior = p->prior;p->prior = s;p->prior->next = s;
D. s->next = p;s->prior = p->prior;p->prior->next = s;p->prior = s;