vjsharma, generally who will refer to people and that will refer to groups or objects. There's a nice explanation here: http://grammar.quickanddirtytips.com/wh ... -that.aspx

Although "that" has been used to refer to people in writing, "who" would be preferred.

"That" is fine to use with plural nouns: The mittens that I took on the ski trip are red.

_________________
Jamie Nelson
ManhattanGMAT Instructor

I still don’t understand why E is wrong. The official explanation refers to “pronouns ambiguity” but since even Tim from ManhattanGMAT Staff confirmed that “they” cannot refer to “a gentile Dutch couple” (singular), there is actually no pronoun ambiguity here.

So what is wrong with E then?
I don’t see that “even though” changes the meaning really since we have “though” in A (original answer), which is supposed to direct the meaning.
Maybe, E is incorrect because we need to have the comma after “Netherlands” in order to separate two independent clauses?
Thanks

D) who were hidden by a gentile Dutch couple during the Nazi occupation of the Netherlands but were eventually discovered

E) who were hidden by a gentile Dutch couple during the Nazi occupation of the Netherlands even though they were eventually discovered

To understand why E is incorrect, let's compare E to the correct answer, D.

Simply, D says "The family was hidden but eventually discovered" whereas E says "The family was hidden even though they were eventually discovered".

Let's contrast "but" with "even though". Consider these sentences:
I studied for weeks BUT I still bombed the test.
I bombed the test EVEN THOUGH I studied for weeks.

Notice that in the first sentence we have more of a logical ordering of events. One thing happened and then another thing happened. The "but" indicates a surprising outcome for the second event given the occurrence of the first event.

In the second sentence, we are saying something recently happened even though something earlier had happened that should have prevented the first occurrence from happening.

Here, this sentence shows two things in sequence: 1) family was hidden and then 2) family was discovered. Because of this, "but" is more appropriate to use.

If you're still not sure, make up some sentences expressing the same information, one using "but" and the other using "even though".

_________________
Jamie Nelson
ManhattanGMAT Instructor