9. 在一个单链表中,已知q所指结点是p所指结点的前驱结点,若在q所指结点和p所指结点之间插入s结点,则执行 ( )(本题4.0分)
A. q->next=s;s->next=q->next;
B. p->next=s->next;s->next=p;
C. q->next=s;s->next=p;
D. p->next=s;s->next=q;