D And F Block Elements

Identify the correct statements about lanthanoids

I. $\mathrm{Ce}^{4+}$ and $\mathrm{Tb}^{4+}$ act as oxidising agents.

II. $\mathrm{Eu}^{2+}$ and $\mathrm{Yb}^{2+}$ act as oxidising agents.

III. Misch metal is an alloy of $95 \%$ iron and $5 \%$ lanthanoid metal.

IV. $\mathrm{La}^{3+}$ and $\mathrm{Ce}^{4+}$ are diamagnetic in nature.