13. （单选题）向一个栈顶指针为 hs 的链式栈中插入一个指针 s 指向的结点时，应执行（ ）

{{ select(1) }}

• hs->next = s;
• s->next = hs; hs = s;
• s->next = hs->next; hs->next = s;
• s->next = hs; hs = hs->next;