C is introducing a future activity/project 介绍新项目,"that we are going to do" 的含义/缩写 >
This is one of the experiments to do in our laboratory (later on,some time in the near future) .
其他的都不可以用因为语法上有错误,根本没有这样的说法.标准英语中只有 do/perform/conduct/ carry out an experiment,没有 make experiment/have experiment.
This is how she did it 选C 用 A/B/D 的单词只能说：
This is what she did
This is the reason (why) she did it
It is a strange thing that she should do this