（2015·茂名）阅读下面文章，根据文章内容，从每小题所给出的A、 B、 C、 D四个选项中选出最佳答案

One morning, Mr Black was driving in the country and looking for a small hotel. When he saw an old woman on the side of the road, he stopped his car and said to the old woman, “I want to go to the Sun Hotel. Do you know it?”

“Yes,” the old woman said,“I will show you the way.” She got into Mr Black’s car and they drove about twelve miles. When they came to a small house, the old woman said, “stop here!” Mr, Black stopped and looked at the house.“But this isn’t a hotel.” He said to the old woman.

“No”the old woman answered, “This is my house. And I'll show you the way to the hotel. Turn round and go back nine miles. Then you’ll see the hotel.”

丁丁假期去我国一处驰名中外的地区旅行，在该地观赏到了以下景观。请运用所学知识完成下题。

下列关于磁感应强度方向的说法中，错误的是（   ）

小明在某商店购买商品A、B共两次，这两次购买商品A、B的数量和费用如表：

若小丽需要购买3个商品A和2个商品B，则她要花费（  ）