The word "potent" (Line1, Para. 1 ) probably means_______.

A．Your emotion and mood affect the curative process a lot.
B．Placebos do no good to a patient's disease.
C．The placebo does little harm, but is helpful to cure the disease.
D．Physicians are often unwilling to give placebos to patients.

A．Many people are disappointed at the effects of snake-oil remedies.
B．Most patients should seek the help of psychologists instead of physicians.
C．Most physicians are happy and ready to preseribe placebos.
D．A placebo can help a patient only psychologically.