A dedicated vent system is defined as what?

A dedicated vent system refers to a vent that is designed to serve only one specific appliance. This ensures that the appliance has a direct path for combustion gases to exit the home, which enhances safety and efficiency. Since no other appliances share this vent, it minimizes the risk of backdrafts or contamination from other vented appliances.

The other options suggest configurations where multiple appliances might share a vent system or imply a more complex setup, which does not align with the definition of a dedicated vent system. Thus, defining a dedicated vent system as the only vent for an appliance emphasizes the focus on a singular, efficient, and safe exit route for the combustion gases produced by that particular appliance.