Explanation:
Spectator ions refers to elements/molecules that do not form part of the reaction. Basically, these elements/molecules are in the same state in the reactant and product side. From the given reaction, Ca and SO4 change their state from aqueous to solid and Na and Cl do not change their state. Therefore, Na and Cl are spectator ions and Ca and SO4 are not spectator ions.
Answer:
The correct option is C.
