一个英语问题 请指教

因为逗号不能连接两个并列分句，故只能用most of whom来构成非限制性定语从句，即把逗号前面的看成主句，逗号后面的看成从句。
要构成两个并列分句：
1 用分号
2 用连词and/so/but/while等，看句子具体意思而定。
I was told that there were about 50 foreign students studying Chinese in the school, most ____of whom______were from Germany.
＝I was told that there were about 50 foreign students studying Chinese in the school； most ____of them______were from Germany.
＝I was told that there were about 50 foreign students studying Chinese in the school，and most ____of them______were from Germany.

欢迎探讨词法语法问题。

因为这两个句子是由逗号连接的
这就说明 这两个句子有一个句子是不完整的。
因为前面的句子里有WAS作谓语，故逗号后面那句不是一个完整的句子，所以不能用them，好像是个定语从句，因为选项是 介词+连词的形式。。
话说AD 和 BC不是一样的么。。？
仅供参考。。

Whom指代前面的所有人.mostthem…是个句子了,但是逗号不能连接句子.

是非限制性定语从句，这里缺少连接词，whom有连接作用，them没有连接作用

非限制性定语从句

选A和D ,都是一样的啦````

因为一个句子只能有一个主语

most of whom 用来修饰 先行词 50 foreign students