The Olympic Games helped to keep peace among the pugnacious states of

Let's apply e-GMAT 3 step process to solve this question:

The Olympic Games helped to keep peace among the pugnacious states of the Greek world in that a sacred truce was proclaimed during the festival's month.

A. world in that a sacred truce was proclaimed during the festival's month
B. world, proclaiming a sacred truce during the festival's month
C. world when they proclaimed a sacred truce for the festival month
D. world, for a sacred truce was proclaimed during the month of the festival
E. world by proclamation of a sacred truce that was for the month of the festival


SENTENCE STRUCTURE

• The Olympic Games helped to keep peace among the pugnacious states of the Greek world
o in that a sacred truce was proclaimed during the festival's month.




• This sentence tells us that the Olympic Games helped to keep peace among otherwise fighting states of the Greek World.
o This became possible because a sacred truce was proclaimed during the month of the festival. Note that, the sentence does not tell us who proclaimed this truce.




ERROR ANALYSIS

1. The phrase “festival’s month” is not idiomatic. It gives the meaning that the festival possesses the month. When referring to an inanimate object, we must avoid possessive. This expression should be “the month of the festival”.
2. Here, the expression “in that” means “because”. In this case, ‘because’ is preferred since it is more concise and gives the meaning directly. Note that ‘for’, which is used in the correct option, also means because.
Also as the OG says, this two-word expression can be replaced with a word for conciseness.


PoE

A. Incorrect for the reasons stated above.

B. Incorrect.
1. The phrase “festival’s month” is incorrect as explained in the error analysis.
2. The verb-ing modifier “proclaiming” seems to modify the preceding clause. Now, when a verb-ing modifier modifies the preceding clause, it should make sense with the subject of the preceding clause. So, this option indicates that the Olympic Games did the action of “proclaiming a sacred truce”.
However, if we refer back to the meaning analysis it was not clear from the original sentence who proclaimed the sacred truce. The Games themselves could not have proclaimed anything. So, this option does not indicate a logically correct meaning.


C. Incorrect
1. The reference of the pronoun ‘they’ is ambiguous. It can refer to “the pugnacious states” or “the Olympic Games”.
2. The original sentence indicates that the truce was proclaimed during the month of the festival. This meaning is not conveyed by this option.


D. Correct.
This option corrects the idiom error from the original sentence and replaces the phrase “in that” with “for”, making the sentence concise.


E. Incorrect.
This option is very wordy as compared to option A and D. Also, it suggests that the proclamation of the sacred truce was done by the Olympic Games. This is not the intended meaning of the sentence.



Hope this helps!

Regards,
Deepak