题目

语法填空 Many teachers believe that hands－on experience is the (good) way to learn. A group of students in the United States are putting that belief to the test. They (success) designed and built a robot for discovering unexplored mines the bottom of the sea. Students made the robot (answer) a challenge from the U．S. Department of Defense. The students recently tested the underwater vehicle (call) PerseusⅡin a 95－meter－long tank of water at the Stevens Institute of Technology. The robot costs about $15,000 to build. The students use a video game control to direct (it) movements若，且，则的最小值是（     ）A．4B． 3C．D．5