The correct answer is: A. Thinner.
Turpentine oil is a solvent that is used to thin oil-based paints. It can also be used to clean brushes and other painting tools. Turpentine oil is a natural product that is derived from pine trees. It is a clear, colorless liquid with a strong odor. Turpentine oil is flammable and should be used with caution.
A thinner is a liquid that is used to reduce the viscosity of a paint or varnish. Thinner makes the paint or varnish easier to apply and helps to improve the finish. Thinner can also be used to clean brushes and other painting tools.
A vehicle is a liquid that is used to suspend pigments in a paint or varnish. The vehicle also helps to transfer the paint or varnish to the surface being painted. The most common vehicles are oil, alkyd, and acrylic.
A base is a substance that is used to provide a foundation for a paint or varnish. The base helps to improve the adhesion of the paint or varnish to the surface being painted. The most common bases are oil, alkyd, and acrylic.
A drier is a substance that is added to paint or varnish to speed up the drying process. Driers can be either natural or synthetic. Natural driers are derived from plants, while synthetic driers are made from chemicals.