What is the voltage reading from terminal G to the load side of the transformer assuming the thermostat is closed and the fan is set to auto?

When assessing the voltage reading from terminal G to the load side of the transformer with the conditions specified—thermostat closed and fan set to auto—it is important to understand the functioning of the system. Terminal G is typically associated with the fan relay circuit, which controls the operation of the fan.

In the auto setting for the fan, the fan will not run unless there is a demand for heating or cooling that activates the system. If the thermostat is closed and there is no call for heat or cool air, the fan does not operate, resulting in no voltage present at terminal G. Thus, the voltage reading between terminal G and the load side of the transformer would indeed be 0 volts because there is no active circuit to provide any voltage under these circumstances.

Consequently, the correct choice reflects the condition of the circuit perfectly, indicating that without an active demand for operation, terminal G remains inactive and registers no voltage to the load side of the transformer.