Arrange the following metal complex/compounds in the increasing order of spin only magnetic moment. Presume all the three, high spin system.

(Atomic numbers Ce = 58, Gd = 64 and Eu = 63)

(a) (NH₄)₂[Ce(NO₃)₆]

(b) Gd(NO₃)₃ and

(c) Eu(NO₃)₃

Given below are two statements :

Statement I : The E^o value for Ce⁴⁺ / Ce³⁺ is + 1.74 V.

Statement II : Ce is more stable in Ce⁴⁺ state than Ce³⁺ state.

In the light of the above statements, choose the most appropriate answer from the options given below :

Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R :

Assertion A : Size of Bk³⁺ ion is less than Np³⁺ ion.

Reason R : The above is a consequence of the lanthanoid contraction.

In the light of the above statements, choose the correct answer from the options given below :

Which one of the following lanthanoids does not form MO₂? [M is lanthanoid metal]