A. p->next=s; s->next=p->next; B. s->next=p->next; p->next=s; C. p->next=s; p->next=s->next; D. p->next=s->next; p->next=s;
A. L=s; s->next=L; B. s->next=L; L=s; C. s=L; s->next=L; D. s->next=L; s=L;
A. L=s;s->next=L; B. s->next=L->next;L->next=s; C. s=L;s->next=L; D. s->next=L; s=L;