Solution:

To determine the direction of the resultant force on the positive charge \(q_0\) placed at the center due to the four charges on the clock face, we analyze the forces exerted by each charge.

Solution Steps:

1. Forces by Opposing Pairs:
- The positive charges at 12 and 3 exert a repulsive force on \(q_0\), while the negative charges at 6 and 9 exert an attractive force on \(q_0\).
- Each pair of opposing charges creates forces with equal magnitudes but different directions.

2. Force Components:
- The force due to the charges at 12 and 6 (along the vertical line) will cancel each other out in the vertical direction, as they are equal and opposite.
- Similarly, the forces due to the charges at 3 and 9 (along the horizontal line) will cancel each other out in the horizontal direction.

3. Resultant Force:
- Since the charges at 12 and 9 are positive and repulsive, they push \(q_0\) away from them.
- The vector sum of these forces results in a net force pointing diagonally between the 6 and 9 positions.

4. Direction:
- The resultant force points toward the 7:30 position, as this is the direction of the net vector resulting from the combination of all four forces.

Thus, the direction of the resultant force on \(q_0\) points to 7:30.