Sentence Correction (SC) | Re: Henry Wadsworth Longfellow was a professor of Modern Languages at Harv

Henry Wadsworth Longfellow was a professor of Modern Languages at [u]Harvard, at the same time also one of America’s greatest poets.

(B) Harvard, and at the same time was also one of America’s greatest poets.

(E) Harvard, being one of America’s greatest poets at the same time.


I believe that in B "at the same time was also" would be redundant on GMAT?
Can someone tell why E is wrong? As for mee it modifies the entire clause