GMAT Sentence Correction (SC) | A powder derived from the North American Echinacea flower,

(A)A powder derived from the North American Echinacea flower, which has been effective in preventingcolds,is grown (A powder cannot be grown. Rather it is derived from flower)
(B)A derivative , which has been effective in preventing colds, of the North American Echinacea flower, is grown(Same as A)
(C) A North American Echinacea flowerderivative , which has been effective in preventing colds is grown(Same as A)
(D) The North American Echinacea flower has a derivative which has been
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