such 有名词的意思,这句话是说,这就是他的善良,人们赞扬他的地方.that引导的是定语从句,修饰限定kindness,
强调句的构成是 it is/was +要强调的部分+ 关系从句,当强调的部分（句子的主语,宾语,状语）是人,用关系词who或whom,有时必须用that,that 可用在任何情况下.
如果你看做是强调句,那么去掉it was ...that以后的句子应该是一个完整的句子.但是你看,去掉以后,句子还原成：
Everybody praised him his kindness.很显然,是个错误的句子,因为它缺少了一个for.
正确的句子应该是：
Everybody praised him for his kindness.
再倒回去,变成强调句的话,就是
It was for his kindess that everybody praised him.这才是正确的.如果照你说的看成强调句,强调的部分是kindness,那么that引导的应该是和强调的部分有关,而不是him .可以说成It was his kindness that made him to be praised.
所以该题如果选a是错误的,是缺少成分的.