I was told that there were about 50 foreign students ________ Chinese in the school, most ________ were from Germany．
A.study; of whomB.study; of themC.studying; of themD.studying; of whom在线课程D
从句子结构来看，前面一空应该是用非谓语动词作定语，所以答案只能从C和D两个选项中选；后一选项从句子中间的逗号可知，应该用代词+of+关系代词，这样答案就只能是D项了。studying为现在分词作定语，表示主动和进行，符合句意。