在一个带头结点且头指针为head的非空双向循环双链表中,删除尾结点的操作是_______。
A.
p=head -> prior ; p -> prior->next=head ; head ->next=p -> prior ; free(p) ;
B.
p=head -> prior ; p -> prior->next=head ; head->prior=p -> prior ; free(p) ;
C.
p=head -> prior ; head->prior=p -> prior ; p -> prior->next=head->next ; free(p) ;
D.
p=head -> prior ; p -> prior->next=head ; head->prior->next=p -> prior ; free(p) ;