The correct answer is option 'C' which states that H = -Grad(V). Let's explain this relation in detail:

1. The relation between the magnetic field intensity (H) and the electric potential (V) is given by the gradient of the electric potential. This means that the magnetic field intensity is equal to the negative gradient of the electric potential.

2. The gradient of a scalar function (in this case, the electric potential) is a vector that points in the direction of the maximum rate of change of the scalar function. It is represented by the operator "Grad" (∇).

3. The negative sign in front of the gradient indicates that the magnetic field intensity is in the opposite direction of the electric potential gradient.

4. In other words, the magnetic field intensity is perpendicular to the equipotential surfaces (surfaces of constant electric potential) and points from higher potential to lower potential.

5. This relation is a fundamental concept in electromagnetism and is described by Maxwell's equations. It shows that changes in the electric potential can induce magnetic fields and vice versa.

Overall, the relation H = -Grad(V) expresses the relationship between the magnetic field intensity and the electric potential. It states that the magnetic field intensity is equal to the negative gradient of the electric potential, indicating the direction and magnitude of the magnetic field generated by changes in the electric potential.