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