The experiment on the monkey to test the new drug, which has already been advertised on TV, requires more money than ________．
A.have been put inB.being put inC.has been put inD.to be put in在线课程C
解析：

试题分析：本题为语法题，考查more…than这一结构的用法。详细
解答：在more…than这一结构中，than后面应跟动词原形，又因为主语是the experiment，所以谓语用单数，故选项C为正确答案。