The process of removing decay is known as

Cavity preparation is the process of removing decay from a tooth. Unlike tooth extraction, which involves removing the entire tooth, cavity preparation only removes the decayed portion and preserves the natural tooth. Root canal is a procedure used to treat infected or damaged nerves inside the tooth, not for removing decay. Scaling is a process used to remove plaque and tartar from the outer surfaces of the teeth, not specifically for decay. Therefore, the best answer is cavity preparation.