Which one has the highest boiling point?

A

He

B

Ne

C

Kr

D

Xe

Among the noble gases, Xe has the highest boiling point.
The boiling points (in K) of He, Ne, Ar, Kr, Xe and Rn are 4.0, 27.0, 87.0, 121, 165.0 and 211 respectively.
On moving down the group, the atomic size increases. Due to this, the polarizability of atom increases and the magnitude of Van der Waal's forces increases. This increases the boiling point.