Which action did Chloe inquire about concerning Tom's behavior?

Chloe's inquiry about Tom's behavior revolves around his actions that seemed irresponsible. By asking about the reasons behind his irresponsible behavior, she demonstrates concern and a desire to understand his motivations. This type of questioning is indicative of seeking clarification on actions that are deemed inappropriate or troubling, which aligns directly with the context that Tom's behavior may have raised questions in Chloe's mind about his judgment or decision-making.

The other options, while they reflect different aspects of behavior, do not capture the essence of Chloe's inquiry regarding Tom's lack of responsibility. For instance, asking if he was calm or if he enjoyed the party focuses on his emotional state or enjoyment levels rather than addressing problematic behavior, while inquiring if he was acting wisely does not directly engage with the issue of irresponsibility. Thus, the choice to ask about his irresponsible actions directly addresses the concern that Chloe has regarding Tom's behavior.