Final answer:
The scenario likely involves bipolar disorder, and the most suitable interaction is to gently inquire about medication adherence, reflecting an understanding of the condition and its management.
Step-by-step explanation:
Considering the behavior described for Mike, it is plausible that he may be experiencing a bipolar disorder, which is characterized by dramatic shifts in energy and mood, affecting an individual's day-to-day functioning. The most helpful and appropriate interaction from John would be option B, 'Mike, have you been taking your medicine?' This suggestion displays concern while also addressing the possibility that Mike's mood swings could be managed with proper medication adherence, which is crucial for those with bipolar disorder. This response is supportive and acknowledges that Mike's condition may require ongoing medical treatment to manage symptoms effectively.