Before its independence in 1947, Britain ruled India as a colony and they would relinquish power only after a long struggle by the native people.
Before its independence in 1947, Britain ruled India as a colony and they would relinquish power
Before independence in 1947, Britain had ruled India as a colony and relinquished power
Before its independence in 1947, India was ruled by Britain as a colony and they relinquished power
Before independence in 1947, India had been ruled as a colony by Britain, which relinquished power
Before independence in 1947, India had been a colony of the British, who relinquished power

I was able to narrow down between D and E. I ultimately chose D because "Who" is used for people only and thought that was a bigger mistake than the wordiness. Can someone explain why "who is okay for a country?" Can who be used for any other subjects other than people?

'the british' isn't a country; it's a group of people, and therefore can serve as a proper antecedent for 'who'.

'britain' is a country, and so would need to take 'which'.

I think the answer to this question should be C and not D or E.

SC book clearly writes about exception to the rule of simple/perfect tenses:
Clauses linked by 'before' or 'after' indicate the time sequence very clearly, so you do not generally need to use the past perfect tense.

In this problem, because of the use of 'before independence', we should use simple past i.e. India was ruled. The only problem I could see in this option though is the use 'its' before the subject is introduced in the sentence.

Ron, tutors - please clarify.

Choice D wordy and confusing...you can read it as a colony that was next to britain...also watch out for 'as' use...it makes the sentence wordy...

Choice C is wrong because of they...who relinquished the power? it's not really clear this way and if it were clear then they should 'it' since India is singular...

I'm not an expert but that's the way I see it...

The main problem with C is the use of 'they' to refer to 'Britain' - "India was ruled by Britain as a colony and they relinquished power".
Even if the rule of tenses is applied 100% of the time (I have my doubts), I would not choose an option in which plural pronoun is used to refer to singular noun.
Tutors,
Can you confirm if the tense rule referred to by viksnme is applicable in every case.

Before its independence in 1947, Britain ruled India as a colony and they would relinquish power only after a long struggle by the native people.

This original sentence has couple of errors.
1) "Its" has no clear antecedent, moreover its use it not at all required.
2) Modifier "Before its independence in 1947" should modify "India" and not "Britain".
3) "Britain" is singular, so use of plural "they" to refer it is incorrect.

A) Original sentence incorrect.
B) Modifier problem is not solved in this option.
C) Modifier problem is solved but "They and Its" problem still intact in this option.
D) Modifier problem is solved but have you ever heard a word such as "ruled as a colony". It is unidiomatic.
E) This option is correct. In normal speech you often say "former British colony, or french colony" so nothing wrong with this phrase. No modifier, "they" or "its" problem. "Who" is unambiguously referring to British.

Please read (and follow!) the forum rules. Your subject line should be the first 5-8 words of the problem.

"before" places the "independence" portion of the sentence relative to the following clause. It does not place the "who relinquished power" portion of the sentence. We still have two events: (1) had been a colony, and (2) the people who relinquished power only after a long struggle. That's our past perfect / simple past mix in this case.

This is not the same thing as saying, for example:
Before she went to the store, she stopped by her mom's house.
Now, the before is actually linking the only two events we have here.

Also, for that before/after rule. It's not saying that you cannot have past perfect - only that it's not required any more. Typically, if the meaning of the sentence is "this one thing happened RIGHT before this other thing - very close in time" then I don't generally use past perfect. If they are still widely separated, though, then I may use it.

Thanks Stacey for the clarification. I understand it better now.

You're welcome!