Hello Everyone!
Let's tackle this question, one issue at a time, and narrow it down to the right choice! It's a pretty short sentence, so this should be a quick one to answer! To start, here is the original question with the major differences between the options highlighted in orange:
Mauritius was a British colony for almost 200 years, excepting for the domains of administration and teaching, the English language was never really spoken on the island.
(A) excepting for
(B) except in
(C) but except in
(D) but excepting for
(E) with the exception of
Okay, to be honest, you could highlight everything in each option because they're short and all different. However, if you look at the entire sentence, carefully, a major clue should jump out at you:
Mauritius was a British colony for almost 200 years, excepting for the domains of administration and teaching, the English language was never really spoken on the island.
We have two INDEPENDENT CLAUSES in here with a phrase separating them. Whenever we have two independent clauses in a sentence, what do we need to have to connect them? A conjunction or a semicolon!
Let's take a look at each sentence with the non-underlined parts worked back in. Make sure that there is some way to separate the two independent clauses that is grammatically correct (a conjunction or semicolon):
(A) Mauritius was a British colony for almost 200 years, excepting for the domains of administration and teaching, the English language was never really spoken on the island.
This is INCORRECT because there is no conjunction to connect the two independent clauses together. It's actually a run-on sentence with a modifier in between to throw you off! A modifier is not good enough to separate two independent clauses - it MUST be a conjunction or semicolon.
(B) Mauritius was a British colony for almost 200 years, except in the domains of administration and teaching, the English language was never really spoken on the island.
This is also INCORRECT because it doesn't have a conjunction to connect our two independent clauses! A modifier in between them isn't good enough!
(C) Mauritius was a British colony for almost 200 years, but except in the domains of administration and teaching, the English language was never really spoken on the island.
This is CORRECT! It uses the coordinating conjunction "but" to combine the two independent clauses together to create one complete sentence.
(D) Mauritius was a British colony for almost 200 years, but excepting for the domains of administration and teaching, the English language was never really spoken on the island.
This is INCORRECT. While it does use the conjunction "but" to combine the two clauses, we have an idiom problem. The phrase "excepting for" is not an acceptable idiom in English. "Except in" or "with the exception of" are the correct forms of this idiom.
(E) Mauritius was a British colony for almost 200 years, with the exception of the domains of administration and teaching, the English language was never really spoken on the island.
This is INCORRECT because it doesn't use a conjunction to connect the two independent clauses. It's one long run-on sentence with a modifier in between, which isn't good enough to work.
There you have it - option C is the correct choice! It's the only one that uses a conjunction to connect two independent clauses together AND doesn't have any idiom issues.
Don't study for the GMAT. Train for it.