Cation Exchange Reaction is an example of . . . . . . . . reaction.

Answer: Option C

Ion exchange reaction is any class of chemical reaction between two substances, each consisting of positively and negatively charged species called ions that involves an exchange of one or more ionic components. Whereas cation exchange reaction involves the exchange of cations only.
The cation exchange reaction is an example of a Reversible and Equivalence reaction. It is used to replace the existing ionic nanocrystalline structure with a different metal ion.