Answers are below...and I have answered this question on the basis of above table.
Explanation :-
(a.) Among nonpolar liquids, those with higher molar masses tend to have normal boiling points that are (lower).
(b.) Among compounds of approximately the same molar mass, those with greater polarities tend to have enthalpies of vaporization that are (higher).
(c.) Xe (Xenon), a substance can exist only as a gas at temperatures above its critical temperature. Of the noble gases listed, only Xe has a critical temperature above O°c.