This may be true, but it doesn’t prove that chemical agents aren’t necessary for treating joint pain. Even if people will switch to using herbal remedies, we still need to know whether the manufacturer’s herbal remedy contains chemical agents that treat joint pain.

The herbal remedy was as effective as a prescription drug that successfully treats joint pain. If the herbal remedy doesn’t contain any chemical agents that treat joint pain, then it’s true that chemical agents aren’t necessary for the successful treatment of joint pain.

It doesn’t matter whether the test participants had used an herbal remedy before; the test still found that the herbal remedy was as effective as the prescription drug. Regardless, (C) doesn’t establish whether the herbal remedy contains chemical agents.

No matter who analyzed the clinical tests, we still don’t know whether the herbal remedy contains chemical agents. If it doesn’t, then the manufacturer’s conclusion follows.

The argument is only addressing whether the prescription drug and the herbal remedy treat joint pain, not whether they eliminate the cause of joint pain. Regardless, (E) fails to establish whether the herbal remedy contains any chemical agents.