If water continues to trickle into the toilet bowl after the device shown in the illustration has apparently closed, the problem is likely due to __________. GS-0155

Correct Answer: Option D — "C" having developed a warp or ripple at the seating surface

A continuous trickle in a flush valve indicates a failure to achieve a positive seal. If the main diaphragm or seat (item C) develops a warp, ripple, or physical damage, it cannot seat properly against the valve body, allowing water to bypass the seal and flow into the bowl.