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

Assertion (A) : An aqueous solution of $$\mathrm{KOH}$$ when used for volumetric analysis, its concentration should be checked before the use.

Reason (R) : On aging, $$\mathrm{KOH}$$ solution absorbs atmospheric $$\mathrm{CO}_{2}$$.

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

The complex cation which has two isomers is :

The structures of major products A, B and C in the following reaction are sequence.

The graph which represents the following reaction is :