Let us not assume that a question by the teacher is more important that a question by the student.
The fundamental reason for the existence of a school is to nurture or develop students. Nurturing happens through a process of inquiry into the questions raised by a student and the capacity of teachers to guide the process of inquiry towards a convincing solution.
His question is his curiosity and it is with findings of his curiosity that learning happens at its best.
Finding answers for students question is more important that the question raised by a teacher, no matter how stupid the question may be.