The kinematic viscosity of a fluid refers to its ability to flow and is defined as the ratio of dynamic viscosity to density. In other words, it is a measure of how easily a fluid can change its shape or deform under the influence of an external force.

Dynamic viscosity, on the other hand, is a measure of the internal friction or resistance to flow within a fluid. It is defined as the ratio of viscous force to the rate of flow.

To understand why the correct answer is option C, let's break down the components of the equation and their significance:

1. Dynamic viscosity (μ): This is a property of the fluid itself and represents its internal resistance to flow. It is a measure of the fluid's thickness or stickiness. The higher the dynamic viscosity, the more resistant the fluid is to flowing. Common units for dynamic viscosity include Pascal-seconds (Pa.s) or poise (P).

2. Density (ρ): Density is a measure of the mass per unit volume of a substance. It represents the compactness or concentration of particles in a fluid. The higher the density, the more mass is packed into a given volume. Common units for density include kilograms per cubic meter (kg/m³) or grams per cubic centimeter (g/cm³).

3. Kinematic viscosity (ν): Kinematic viscosity is defined as the ratio of dynamic viscosity to density. It provides a measure of how easily a fluid can flow relative to its density. It is a key parameter in fluid dynamics and is used to characterize the behavior of fluids in various applications. Common units for kinematic viscosity include square meters per second (m²/s) or stokes (St).

By dividing dynamic viscosity by density, we eliminate the influence of density and obtain a measure of the fluid's ability to flow independent of its concentration. This allows for a more direct comparison between different fluids, regardless of their densities. The resulting kinematic viscosity value is a measure of the fluid's internal resistance to flow relative to its density.