二、设单链表中结点的结构为   typedef struct node { //链表结点定义   ElemType data; //数据   struct node * Link; //结点后继指针   } ListNode;   (1) 已知指针p所指结点不是尾结点,若在*p之后插入结点*s,则应执行下列哪一个操作?   A. s->link = p; p->link = s;   B. s->link = p->link; p->link = s;   C. s->link = p->link; p = s;   D. p->link = s; s->l