Which of the following gases exists more abundantly in nature than the others?

Given below are two statements:
Statement-$I$: Noble gases have very high boiling points.
Statement-$II$: Noble gases are monoatomic gases. They are held together by strong dispersion forces. Because of this,they are liquefied at very low temperatures. Hence,they have very high boiling points.
In the light of the above statements,choose the correct answer from the options given below:

What is the oxidation state of $Xe$ in $XeOF_4$?

Which elements were discovered by the scientists Ramsay and Glenn $T$. Seaborg?

Which among the following gases is used in the treatment of cancer?

Which of the following pairs of inert gases is used in flash bulbs?