tarek99 wrote:
Greatly influenced by the Protested missionary Samuel Kirkland, the Oneida was the only one of the five-nation Iroquois League who sided with the colonists during the American Revolution.
A. was the only one of the five-nation Iroquois League who sided
B. was alone of the five-nation Iroquois League when they sided
C. alone among the five-nation Iroquois League sided
D. were the only ones out of the five nations of Iroquois League in siding
E. only of the five-nation Iroquois League had sided
Similar to the usage of -- "The Americans" or "The French", "The Oneida" is a plural subject and thus requires a PLURAL VERB "were" and not "was". Thus, A and B are incorrect for PRONOUN NUMBER AGREEMENT error.
Choice d is wrong because it is extremely, incredibly wordy. 'out of' is also a problem (because the GMAT would only use
'out of' if it meant literally out of something, or in standard idioms like '3 out of 4').
choice e is wrong because it uses the past perfect to refer to a single event. you need the simple past here (just 'sided', not 'had sided'), because there is no more recent time signal to justify the use of the past perfect for the 'earlier' event.
Thus, choice C is correct.