The correct answer is D. An Imhoff cone.
An Imhoff cone is a laboratory apparatus used to measure the amount of settleable solids in a liquid. It is a cone-shaped vessel with a base diameter of 100 mm and a height of 200 mm. The cone is filled with the liquid to be tested and then allowed to stand for one hour. The amount of solids that settle to the bottom of the cone is then measured.
A jar is a cylindrical container with a flat bottom and a lid. It is used to store and transport liquids.
A breaker is a machine used to break up large pieces of material. It can be used to break up rocks, concrete, or other materials.
A test tube is a small, cylindrical glass tube with a closed end. It is used to hold small amounts of liquids or solids.
The Imhoff cone is the best choice for measuring the amount of settleable solids in a liquid because it is specifically designed for this purpose. The other options are not as accurate or precise.