Which noble gas is used in cryogenic studies?

The order of liquefaction of noble gases is:

$SbF_5$ reacts with $XeF_4$ to form an adduct. The shapes of cation and anion in the adduct are respectively:

Match the Xenon compounds in Column-$I$ with their structures in Column-$II$.

Column-$I$	Column-$II$
$(a)$ $XeF_4$	$(i)$ pyramidal
$(b)$ $XeF_6$	(ii) square planar
$(c)$ $XeOF_4$	(iii) distorted octahedral
$(d)$ $XeO_3$	(iv) square pyramidal

The reaction of $Xe$ and $O_2F_2$ gives a $Xe$ compound $P$. The number of moles of $HF$ produced by the complete hydrolysis of $1 \ mol$ of $P$ is. . . . . .

Assertion $(A)$: The boiling points of noble gases increase from $He$ to $Xe$.
Reason $(R)$: The interatomic van der Waals' attractive forces increase from $He$ to $Xe$.
The correct answer is: