(A) Treating bodily disorders by noninvasive methods is generally painless, and these methods -- Contrast is gone as is intended in the sentence. Eliminate.
(B) Treating bodily disorders by noninvasive methods is generally painless, but they
(C) to treat bodily disorders with noninvasive methods is generally painless, but they
B & C gone due to illogical meaning created by "they" pronoun that is referring back to "disorders".
Disorders are less likely than disorders of conventional western medicine to result in permanent healing. Completely illogical meaning
(D) Although to treat bodily disorders by noninvasive methods is generally painless, these methods -- Just doesn't sound good. E sounds way better. I'm unable to spot the error per se, honestly.
(E) Although treating bodily disorders by noninvasive methods is generally painless, these methods -- Correct.
Can someone help with elimination of D?