Q: 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, which had 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
Dear expert, isn't 'E' a case of the comma splice, because 'the incan highway was over 2500 miles long' is an independent clause, and this clause is separated with only a comma after 'Columbus'. Is my understanding wrong?
And in "C", some people commented that the 'verb for road system' is missing. But why cant 'was', found after the non-essential clause 'the incan highway', act as a verb? if so, why is "C' wrong?
Thanks for explanation!