Magnetic flux is a measure of the total magnetic field passing through a given surface area. It is defined as the product of the magnetic field strength and the area perpendicular to the magnetic field. In this case, the magnetic field is parallel to the surface area, which means that the field lines are not passing through the surface. Therefore, the magnetic flux produced when the magnetic field is parallel to the surface area is zero.

Explanation:
Below is a detailed explanation of why the magnetic flux is zero when the magnetic field is parallel to the surface area.

1. Magnetic flux definition:
- Magnetic flux (Φ) is defined as the total magnetic field passing through a given surface area.
- It is calculated by taking the dot product of the magnetic field vector (B) and the area vector (A) of the surface.
- Mathematically, Φ = B · A, where · represents the dot product.

2. Magnetic field parallel to the surface:
- When the magnetic field is parallel to the surface, it means that the magnetic field lines are running parallel to the surface and not passing through it.
- This implies that the magnetic field vector (B) and the area vector (A) are perpendicular to each other, resulting in a dot product of zero.
- Since the dot product is zero, the magnetic flux (Φ) will be zero as well.

3. Zero magnetic flux:
- A zero magnetic flux means that no magnetic field lines are passing through the surface.
- It indicates that the surface is not experiencing any magnetic field, or the magnetic field is not penetrating the surface.
- In the case of a magnetic field parallel to the surface, the field lines are not crossing the surface, resulting in zero magnetic flux.

Therefore, the correct answer is option 'C' - Zero. When the magnetic field is parallel to the surface area, the magnetic flux produced is zero.