ANS:C - with a W.C. trap

An antisyphonage pipe, also known as an anti-siphon or anti-siphoning pipe, is typically fitted with a W.C. (water closet) trap. The purpose of an antisyphonage pipe is to prevent the siphoning of water from the trap in the W.C. This siphoning can occur due to negative pressure or suction in the sewer line, which can lead to the loss of the water seal in the trap. If the water seal is lost, foul gases and odors from the sewer can enter the building through the drainage system. By fitting an antisyphonage pipe to the W.C. trap, it provides an additional vent for air to enter the system, preventing the formation of a vacuum and maintaining the water seal in the trap. This ensures that the trap functions effectively in preventing sewer gases from entering the building. Therefore, the correct statement is:

• With a W.C. trap