GMAT Sentence Correction (SC) | Re: In feudal Europe, urban areas developed from clusters of

Hi...
Can some one explain answer choice B and E...
As per the explanation given by ywilfred... E is awkward...(from which they commuted to farmlands)
IMO B sounds that way... (houses where peasants lived and from which they commuted)
Can some one help me explain the same in detail...
Thanks in advance

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