Which of the following element is isodiaphere of ${}_{92}^{238}U$?

The correct option is C

${}_{90}^{234}Th$

In nuclear physics and radioactivity, isodiaphers refers to nuclides which have different atomic numbers and mass numbers but the same neutron excess, which is the difference between numbers of neutrons and protons in the nucleus. For example, for both ${}_{90}^{234}Th$ and ${}_{92}^{238}U$ the difference between the neutron number (N) and proton number (Z) is N − Z = 54.