An older adult with suspected Parkinson's disease has a "challenge test" performed in order to confirm the diagnosis. The nurse understands that a "challenge test" will demonstrate which of the following?

A. Immediate reversal of all symptoms is unrealistic—while levodopa can improve symptoms, it does not completely reverse the disease or do so instantly. B. A “challenge test” involves administering levodopa to see if there is a dramatic improvement in overall Parkinsonian symptoms, such as tremor, rigidity, and bradykinesia. A positive response supports the diagnosis of Parkinson’s disease. C. Improvement in tremor only is too narrow and not reflective of the full purpose of the challenge test. D. Improvement in gait only also limits the test’s scope—the response is evaluated based on multiple motor symptoms, not just gait.