关于theirs的问题

yamani0304

有这么一道题:

In election held in 1982, an unusual number of well-known political figures campaigned on behalf of children_____who were running for their office.

答案是 of theirs.   答案解释说,theirs是指,their children.这个是不是和我们平时所说的the rubber of mine...是一个类型的呢,但是如果是的话,那么它后边的那个定语从句who是指什么呢?是指theirs么?但是答案同时还说theirs是their children啊.彻底晕了,希望大家帮我

consonant

[In election held in 1982], an unusual number of well-known political figures campaigned on behalf of children of theirs who were running for their office.

简化句子->figures campaigned on behalf of children of theirs who were running for ...

一般来说引导代词都是指代和它靠的最近的那个名词。所以who->theirs

一些领导人物会参加他们那些要竞选官职的孩子的代表，