A) plenum chamber is the correct answer. The plenum chamber is the chamber where the ductwork originates in an air conditioning system. This is the main chamber that distributes the conditioned air throughout the system and into the living or working space. The other answer choices are incorrect because: B) exhaust chamber refers to the part of the system that expels used air, not where the ductwork starts. C) vapor chamber is not a standard term used in air conditioning systems. D) intake chamber would refer to where the system draws in air, not where the ductwork begins.