Which among $KI, FeSO_4, K_2MnO_4, KMnO_4$ cannot be oxidised by $O_3$?

Statement $I$: Sodium hydride can be used as an oxidising agent.
Statement $II$: The lone pair of electrons on nitrogen in pyridine makes it basic.
Choose the $CORRECT$ answer from the options given below:

The element which never acts as a reducing agent in a chemical reaction is

Identify the reductant in the following reaction: $C_2O_4^{2-} + MnO_4^{-} + H^{+} \longrightarrow Mn^{2+} + CO_2 + H_2O$

Which of the following cannot act as a reducing agent?

Which of the following is not oxidized by $O_3$?