💡 Detailed Explanation
The professor states that the core problem is that the proposal doesn't clearly convey 'what' the student wants to clarify and 'what' its academic significance is. She summarizes this by saying the '問い' (research question) is not clear. This directly corresponds to the correct answer. She explicitly says the theme itself is fine ('着眼点は悪くない'), that there is abundant preceding research ('先行研究も豊富にある'), and that the problem is at a stage before the analysis method ('そこに至る前の段階ね'), making the other options incorrect.