In what way can patients exercise caution where TCM theraples are concerned?
A. learn enough about herbal medicines to buy and use them on their own
B. consider the unverifiable nature of TCM theraples and stick with conventional theraples
C. research the effects of herbal medicines on conventional medicines and use them with a doctor's guidance
D.use TCM therapies only in countries where it is the main form of medicine practiced
E.use conventional medicines for pain relief because acupuncture works no better than a placebo