The correct answer is: B. Solvent
A solvent is a substance that dissolves another substance, known as the solute. The solvent is the component of a solution that is present in greater amount. In paints, the solvent is a volatile substance that is added to make the paint easier to apply and to help it dry quickly.
The base is the pigment or colorant in a paint. It is the substance that gives the paint its color. The vehicle is the binder that holds the pigment and solvent together. It is the substance that makes the paint adhere to the surface being painted.
Option A is incorrect because the base is the pigment or colorant in a paint, not the solvent. Option C is incorrect because the vehicle is the binder that holds the pigment and solvent together, not the solvent. Option D is incorrect because the solvent is a necessary component of paint, not something that is not needed.