GMAT Sentence Correction (SC) | Re: Thelonious Monk, who was a jazz pianist and composer,

Thelonious Monk, who was a jazz pianist and composer, produced a body of work both rooted in the
stride-piano tradition of Willie (The Lion) Smith and Duke Ellington, yet in many ways he stood apart
from the mainstream jazz repertory.

A. Thelonious Monk, who was a jazz pianist and composer, produced a body of work both rooted
What is “both” doing here ?
‘The body of work” can be rooted both in X and Y, where X and Y has to be parallel. However, here X and Y are NOT parallel.

B. Thelonious
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