Final answer:
The correct option is B) RH to furnace and RC to Ac.
Step-by-step explanation:
In a three-wire system, the furnace is typically wired to the RH terminal and the AC is wired to the RC terminal. This configuration allows for separate control of the heating and cooling systems.
The RH terminal is used to provide power to the heating system, while the RC terminal is used to provide power to the cooling system. By wiring the furnace to the RH terminal, and the AC to the RC terminal, you can control each system independently.