💡 Detailed Explanation
The speaker is expressing her dissatisfaction and lack of conviction ('納得いかない'). The best response is to show empathy and agreement, such as 'I know, right? I wish he'd explained a bit more.' ('だよね。もう少し説明してほしかったよね。'). Option 1 directly contradicts her feelings. Option 2 offers a solution, which is a possible response, but less immediate and empathetic than simply agreeing with her feeling of dissatisfaction.