Which option can be inferred from the following scenario?

You come home from work on a summer afternoon and notice your home is warmer than usual. You check the thermostat. The room temperature is set at 78°F, so the house should seem cooler. You lower the temperature on the thermostat several degrees in order for the air conditioner to work.

The temperature on the thermostat should be set lower than 78°F.

The air conditioner is not functioning properly.

The air conditioner was turned off.

The thermostat is faulty and may need calibration.