This is really sneaky. Of course it's going to be "Absolute Zero" ... the bottom of the Kelvin scale ... but what in the world is the difference between choice-C and choice-D ? ?
On the Kelvin scale, just to be different I guess, the unit of temperature is not called "the degree" Kelvin. On that scale, the unit is called "the Kelvin", and the temperature is called 'so many' "Kelvins".
So the correct choice is D ... "zero Kelvins".
