Correct answer is (d) setting, laying, bed concreting and connection to drains
To elaborate: A gully is a landform created by running water, eroding sharply into soil, typically on a hillside. Gullies resemble large ditches or small valleys, but are metres to tens of metres in depth and width.
The word siphon is used to refer to a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in an inverted ‘U’ shape, which causes a liquid to flow upward, above the surface of a reservoir, with no pump, but powered by the fall of the liquid as it flows down the tube under the pull of gravity, then discharging at a level lower than the surface of the reservoir from which it came.
Intercepting traps fitted in the length of a house drain, close to its connection to the sewer, which provides a water seal against foul gases rising up into the drain.