Sentence Correction

MGMAT says this is acceptable :

Our system of Presidential elections favors states, such as Delaware, that by population are over-represented in the Electoral College.

Is this acceptable as per GMAT ? I havent see OA with ",That" form I understand the point of the author that there is no other way of writing the above sentence. Does anyone know whether or not this form is tested ?


Thanks
Voodoo[/u]

Hi,
In this example, the comma belongs to the non-essential modifier 'such as Delaware'. So, it is perfectly fine. comma can be used before that only if the comma belongs to the modifier.

If we remove the modifier, the sentence will be :
Our system of Presidential elections favors states that by population are over-represented in the Electoral College. (Correct)

I do not remember seeing such a thing in any of the official materials.