The input power for a thermostat is wired to the

A. R

b. G

c. W

d. Y

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.