You have samples of four compounds: dimethyl ether, methane, difluoromethane, and ethanol. You measure the boiling points of the compounds as -128 °C, -52 °C, -25 °C, and 78 °C, but then lose the labels for each sample. Make the following predictions: 

(a) Which compound boils at -128 °C? 

(b) Which boils at -52 °C? 

(c) Which boils at -25 °C? 

(d) Which boils at 78 °C?