Answer: Option (A) is the correct answer.
Explanation:
Transition elements are the elements that have incompletely filled d-orbitals. Their general electronic configuration is ns (n-1)d.
For example, Ti has atomic number 22 and its electronic configuration is [tex][Ar]4s^{2}3d^{2}[/tex].
Due to similar energies in ns and (n-1)d orbitals electrons can be easily transferred. This causes transition metals to show variable oxidation states.
Thus, we can conclude that it is true regarding the transition elements that multiple oxidation states resulting from the involvement of d electrons in bonding is a characteristic of transition elements.
