A. s->prior=p->prior ; p->prior->next=s ; s->next=p ; p->prior=s

B. p->prior=s ; s->prior=p->prior ; p->prior->next=s ; s->next=p

C. s->prior=p->prior ; p->prior=s ; p->prior->next=s ; s->next=p

D. s->prior=p->prior ; p->prior->next=s ; s->next=p->next ; p->prior->next=s