The correct answer is D. Leader.
A teacher should behave with the students as a leader. A teacher should be able to guide and motivate students to learn and grow. They should also be able to create a positive and supportive learning environment.
A teacher should not behave as a general, as this would create a top-down hierarchy where students are not given the opportunity to participate in their own learning. A teacher should also not behave as a father, as this would create an unhealthy power dynamic where students are not able to challenge the teacher or express their own opinions. Finally, a teacher should not behave as a friend, as this would create a conflict of interest where the teacher is not able to be objective in their assessment of students.
A teacher should be a leader who is able to create a positive and supportive learning environment where students can thrive.