Jonah Swann studies at Reed Middle School in the US. But after school, the 13-year-old boy works as the CEO of The Kandle Company, which makes candles. Swann's candles are different from most other candles on the market. They are made of soy wax(大豆蜡)and have non-zinc wicks（无锌蜡烛芯）. This makes them burn cleanly.

    When Swann was younger, he was interested in business. But business classes were not enough for him. He wanted to run a real business on his own. Luckily, he soon got the chance to do so. A family friend bought a machine that makes candles. Later, he gave the machine to Swann. Swann worked hard in making his own candles. He had to learn how to use the machine, find the right ingredients (原料)and find out how to sell his candles. He tried his best to make his candles look attractive(吸引人的).

    For Swann, making money is not his goal. He plans to give away at least 10 percent of his money to his school. It will be used to support study programs. In fact, he has given some money to a business club at his school. It will start in September. The club will invite some speakers to share their business experience.

下列各句中，标点符号使用正确的一项是 （ ） 

已知映射$f:p\left(m,n\right)\to \left(\sqrt{m},\sqrt{n}\right)\left(m\ge 0,n\ge 0\right)$，设点A（1，3），B（2，2），点M是线段AB上一动点，f：M→M²，当点M在线段AB上从点A开始运动到点B结束时，点M的对应点M²所经过的路线长度为____ ．

材料一：西部某省区地理环境及资源示意图。

材料二：图示区域是中国“一带一路”倡议“陆上丝绸之路经济带”中的“核心区”，是为我国西部内陆地区与中亚、欧洲贸易往来的重要陆上通道。