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Which one of the four great classics in TCM whose authorship is definitely known?
A.
Huangdi Neiiing(Huangdi's Internal Classic)
B.
Nan Jing ( Classic of Difficulties)
C.
Shanghan Zabing Lun (Treatise on Cold Damage and Miscellaneous Diseases).
D.
Shennong Bencao Jing (shennong's Classic of Materia Medica)