This is the 216th most frequent Korean word.
질문에
"To the question" or "on the question."
질문에 is used here to indicate 'to your question', showing direction or target of readiness.
저는 당신의 질문에 대답할 준비가 되었습니다.
I am ready to answer your question.
질문에 denotes 'to his question', specifying the subject or basis of the necessity.
그의 질문에 명확한 답이 필요합니다.
A clear answer to his question is needed.
질문에 demonstrates 'to the teacher's question', pointing out the focus of their effort.