b.in which 是正确选项.题目been后面打少了个made,完整的句子是：The science of medicine,【in which 】progress has been 【made】 very lately ,is perhaps the most inportant of all sciences.这是个非限制性定...如果 in which 换成 whose 或 of which 在非限制性定语从句中做定语这样理解可以吗？这里不能用whose 或of which，关系代词不是做定语，而是做状语。不过i可以用where。你看清楚了吗？是不是打少了个made？