Refer to the figure below of the primary control system of a gas furnace. Consider this trouble shooting situation. Given: The furnace is cold. One lead of a volt meter is connected to point A. The readings between this point and the others are as follows: A to B = 24 volts, A to C = 24 volts, A to F = 0 volts, A to G = 0 volts. Which one of the following components has failed?

Refer to the figure below of the primary control system of a gas furnace. Consider this trouble shooting situation. Given: The furnace is cold. One lead of a volt meter is connected to point A. The readings between this point and the others are as follows: A to B = 24 volts, A to C = 24 volts, A to F = 0 volts, A to G = 0 volts. Which one of the following components has failed?