Here's a problem to solve: What happens when the temperature in the house is cooler than the temperature selected on the thermostat?

Among the 4 following options, which is the correct answer?

- A: The furnace will overheat.
 
- B: The thermostat will become hot.
 
- C: The furnace will automatically turn on.
 
- D: The thermostat will give off a beeping sound.
 