Answer:
A. R
Explanation:
There are basically two wires that supply input power to the thermostat namely the C wire which is the common wire and the R wire .The G wire simply completes the input power circuit from the R-leg of the power supply.On the another hand the Y wire also completes the circuit from the compressor fan contactor to the R-leg of the power supply . While the W wire completes the path to the heater contactor coil.
