Step 1: Understand the question.
We must choose how a teacher should ideally behave with students.
Step 2: Recall modern pedagogy.
Today's education is learner-centred, where the teacher acts as an approachable facilitator.
Step 3: Test option A (General).
A vague general manner gives no warmth or connection, so it is weak.
Step 4: Test option B (Like a Father).
A father-like role can create hierarchy and distance, limiting open expression.
Step 5: Test option D (Like a Leader).
A leader-like role keeps authority on top, again creating distance.
Step 6: Confirm option C (Like a Friend).
Being friendly makes the teacher approachable and trustworthy while keeping professional limits, encouraging participation and emotional security.
Step 7: Conclude.
The most suitable role is to be like a friend.
\[ \boxed{\text{C. Like a Friend}} \]