Final answer:
The best question to ask would be if there is a symptom that only J has, since it is known that J and K have at least one shared symptom. This question facilitates symptom differentiation, which is a common approach in medical diagnostics.
Step-by-step explanation:
When assessing whether J and K have at least one symptom in common, we can eliminate certain options. For instance, choices B) "Are J and K symptom-free?" and D) "Are there no symptoms common to both J and K?" are not viable because they contradict the premise that J and K share at least one symptom. The most relevant question to ask yourself would be C) "Is there a symptom that only J has?" This question directly addresses the condition provided and attempts to further differentiate the symptoms between the individuals. It aligns with medical diagnostic processes where symptom differentiation helps to narrow down potential diagnoses. When considering diagnoses, medical professionals often start by seeking to confirm shared symptoms and then proceed to identify unique symptoms that could point to specific conditions or diseases. In similar clinical scenarios, determining whether two patients share all symptoms or have distinct ones can provide clues and guide the need for further testing or referral to a specialist.