Given below are two statements :

Statement I : Colourless cupric metaborate is reduced to cuprous metaborate in a luminous flame.

Statement II : Cuprous metaborate is obtained by heating boric anhydride and copper sulphate in a non-luminous flame.

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

Mischmetal is an alloy consisting mainly of :

The set that contains atomic numbers of only transition elements, is :

The lanthanoid that does NOT show +4 oxidation state is :