请阅读下面短文,根据短文内容从每小题所给的A、B、C、D四个选项中选出最佳选项。16-year-old Yang Jun'ao, a student from No. 1 Middle School in Nanxian County, Hunan province, invented a robot to help harvest lotus roots(采藕).
"I got the idea when I saw my grandmother, in her 70s, working hard to harvest lotus roots under the hot sun, " Yang said. Sometimes, his grandmother would badly hurt her fingers while using harvesting tools.
To make things easier for his grandmother, he decided to invent a robot that could do the job for her.
With the help of his teacher, Hong Wei, Yang spent almost a year building a model of the robot. The robot can move by itself in the muddy(泥泞的) fields where lotus roots grow. It uses special technology to identify ripe roots by looking at the color of the lotus leaves. Then, its arm carefully cuts the roots without harming them.
While creating the robot, Yang faced challenges like collecting parts for the model, putting them together and using a hot glue gun for connecting. "The first time I used a hot glue gun, my hands were shaking, " Yang laughed. At first, he planned to use rotating blades(旋转叶片) for harvesting lotus roots. But it was hard to find them, so he used more common blades instead.
When Yang showed the robot to his grandmother, she was happy and gave helpful suggestions for improvement. She suggested using a voice player to help locate the robot in thick lotus leaves. "My grandmother's suggestion reminded me that any invention must be practical to be truly valuable. " said Yang.
Although Yang still needs to make improvements, like finding cheaper materials, his teacher Hong spoke highly of Yang's creative thinking and resolution to help his hometown.