The correct answer is: A. Plaster of Paris.
Plaster of Paris is a white powder that is made from gypsum. It is used to make casts, molds, and other items that need to be strong and durable. When plaster of Paris is mixed with water, it forms a hard, solid mass. This makes it ideal for use in X-ray rooms, as it will not interfere with the X-rays.
Barium plaster is a type of plaster that is made from barium sulfate. It is used to coat the inside of the stomach and intestines before X-rays are taken. This helps to make the organs more visible on the X-ray.
Martin’s cement is a type of cement that is made from Portland cement, sand, and water. It is used to make concrete and other building materials.
Keen’s cement is a type of cement that is made from Portland cement, silica, and alumina. It is used to make fireproof materials.
Plaster of Paris is the best option for X-ray rooms because it is strong, durable, and will not interfere with the X-rays.