The Open-Hidden Paradigm in Pain Research Has Demonstrated

The open-hidden paradigm in pain research has demonstrated:

A) inert medicines administered to patients who believe they have pain-killing actions can reduce patients' reported pain levels
B) inert medicines administered to patients who are told that the treatments are placebos can reduce patients' reported pain levels
C) hidden administration of an analgesic medication diminishes patient response
D) uncontrollable noxious stimuli are perceived by patients as more painful than controllable stimuli