For the best extraction of the flavor of saffron threads, it should be soaked in liquid after being pounded with a mortar and pestle.
(A) For the best extraction of the flavor of saffron threads, it should be soaked in liquid after being pounded
(B) To best extract their flavor, saffron threads should be soaked in liquid after pounding
(C) The best way to extract the flavor from saffron threads is soaking them in liquid after being pounded
(D) The best way to extract the flavor from saffron threads is to soak them in liquid after pounding them
(E) The flavor of saffron threads can best be extracted by soaking it in liquid after pounding it
The mistake in the original sentence is the pronoun 'it' which refers to the plural noun 'saffron threads'
A INCORRECT as explained above
B INCOR the modifier pounding cant refer to the subject saffron threads
C INCOR the modifier being pounded is not paralleled with the modifier soaking
D CORRECT pounding is prarallel with to soak
E incor wrong pronoun
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