Final answer:
The prone position refers to lying face down or on one's belly, which is the correct answer to the question about patient positioning.
Step-by-step explanation:
Telling a patient to assume the prone position is the same as saying lie down on your belly. The term 'prone' refers to a face-down orientation of the body, as opposed to 'supine', which describes a face-up orientation. These terms are particularly relevant in clinical settings, where body orientation can be crucial during physical examinations or surgical procedures.
The correct answer from the provided options is D. lie down on your belly. This position is utilized in various medical and healthcare contexts and is distinct from other positions such as standing upright, lying on one's side, or lying on one's back.