It is amazing how a teacher comes to life when he is teaching something he is passionate about.
A tanár megválaszolja a diák kérdését.
The teacher answers the student’s question.
So keep in mind that the direct object is not the student. It is the question.
If he were answering the student, it would be an indirect conjugation, because there would be no direct object at all:
A tanár válaszol a diáknak.
The teacher answers the student.