Q. 29
The greatest road system built in the Americas prior to the arrival of Christopher
Columbus was the Incan highway, which, over 2,500 miles long and extending from
northern Ecuador through Peru to Southern Chile.

A. Columbus was the Incan highway, which, over 2,500 miles long and extending
B. Columbus was the Incan highway, over 2,500 miles in length, and extended
C. Columbus, the Incan highway, which was over 2,500 miles in length and
extended
D. Columbus, the Incan highway, being over 2,500 miles in length, was extended
E. Columbus, the Incan highway was over 2,500 miles long, extending

What is the correct ans according to you and why.
Thanks.

all others are grammatically incorrect

Undoubtedly option (b) that is!

Samy, I hate to disagree with our anonymous guest, but I'm feeling the urge. Lets take a quick look at each answer choice individually:

The greatest road system built in the Americas prior to the arrival of Christopher
Columbus was the Incan highway, which, over 2,500 miles long and extending from
northern Ecuador through Peru to Southern Chile.

A. Columbus was the Incan highway, which, over 2,500 miles long and extending
-though the modifier which correctly describes highway, the "sentence" is actually a sentence fragment, as the which needs to be followed by a verb (preferably "was")

B. Columbus was the Incan highway, over 2,500 miles in length, and extended
-the use of extended in the absence of which was is incorrect; the proper construction should be extending (as extended gives the impression that the road was intentionally lengthened rather than simply existing between two points).

C. Columbus, the Incan highway, which was over 2,500 miles in length and
extended
-since the phrase the Incan highway is set off by commas, the entire introductory modifier is describing the Incan highway. As a result, the which is unnecessary since it creates a sentence fragment.

D. Columbus, the Incan highway, being over 2,500 miles in length, was extended
-BEING IS BAD!!!!

E. Columbus, the Incan highway was over 2,500 miles long, extending
-The introductory phrase The greatest road system built in the Americas prior to the arrival of Christopher
Columbus properly describes the Incan highway. Furthermore, the subordinate phrase extending from
northern Ecuador through Peru to Southern Chile provides additional information about the length of the highway in a manner that is grammatically correct.

Though tricky, the correct answer is E.

-dan