如图是电源电压恒为220V的电热烘干箱的基本电路图，S是双掷开关，R₁是发热电阻，定值电阻R₂为110Ω，当S接“2”时，R₁的电功率是110W，试求：

下列山脉中，既位于第二、第三阶梯分界线上，又是省级行政区大致界线的是（    ）。

根据短文内容，选择正确答案。

    Peter was a small boy. He lived with his parents in a small house near some hills. The people there were all poor.

    One night it was very dry and windy. When everybody was asleep, Peter suddenly heard some noise. It came out from the kitchen. He got up and walked to the kitchen. He found that the wood beside the stove was burning. There was no water tap (水龙头) in the house, so he could not put out the fire. He shouted loudly to wake up everyone in the house. Then he ran out of his house and knocked on the doors of many houses to wake the people up. They all left their houses quickly.

    At last the firemen put out the fire. Many people lost their homes. But luckily, all of them escaped the fire with a whole skin.

                                                                                              南辕北辙
　　今者臣来，见人于大行，方北面而持其驾①，告臣曰：“我欲之②楚。”臣曰：“君之楚，将奚为北面?”曰：“吾马良!”臣曰：“马虽良，此非楚之路也。”曰：“吾用③多!”臣曰：“用虽多，此非楚之路也。”曰：“吾御者④善!”此数者愈善，而离楚愈远耳。
注释：①持其驾：拿着缰绳，驾着他的车子。②之：动词，往，到。③用：资用，即路费。④御者：驾车的仆夫。