Option (c)

(C) option gives the most perfect answer. The first reason is that poetic cadence treaded on structuralist ground which made many academicians to believe that it was structural.
Look at these lines "it is true, treading on structuralist ground:" and "is the assumption that poetic resonance must be interpreted as either ideological or, alternatively, structural in an essentialist, naively psychologised manner".
All the other answers are not complete.