Which of the following sets lists only correct expressions for the electric power P dissipated in a single resistor carrying current I, potential difference V, and resistance R?
a) P=2VI,P=I2R,P=RV2
b) P=VI,P=21I2R,P=RV2
c) P=VI,P=I2R,P=RV2
d) P=VI,P=I2R,P=2RV2