Correct option is (b) Kr is obtained during radioactive disintegration
Air is also the most important source for the other noble gases. T races of krypton are found in various minerals, the most important source of Krypton is Earth's atmosphere. Helium obtained from natural gas and radon is obtained as a byproduct during radioactive disintegration.
So Rn is obtained during radioactive disintegration not Kr.
So Krypton is obtained during radioactive disintegration is the wrong statement.
