Final answer:
Rough-in plumbing is the installation of the drainage, water supply, vent piping, and fixture supports before the actual fixtures are put in place.
Step-by-step explanation:
The installation of all parts of a plumbing system that can be completed prior to the installation of fixtures is known as rough-in plumbing. This stage includes the setup of drainage, water supply, vent piping, and all the necessary supports for fixtures that will be installed later. After rough-in plumbing, inspections usually take place to ensure that the work complies with building codes before the fixtures are installed. Therefore, the correct answer is a. Rough-in plumbing.