Sentence Correction (SC) | Re: At the time of the Mexican agrarian revolution

It took me a very long time to understand the sentence...

I will try explaining the reason between A and E.

If we break the sentence in parts....

At the time of the ........, the most radical faction,....,proposed a return to communal ownership of.....,to what had been a pre-Columbian form of ownership respected by Spaniards

In E, the sentence reads

At the time of the Mexican agrarian revolution, the most radical faction,...., proposed a return to communal ownership of land,that had been a pre-Columbian form of ownership respected by the Spaniards