The given reaction is: \[ \text{Acid} + X \rightarrow \text{Salt} + CO_2 + \text{Water} \] For this reaction, X can be a metal carbonate or a metal hydrogen carbonate, as both of these react with acids to release carbon dioxide, salt, and water. However, metal hydroxides do not release carbon dioxide when they react with acids; instead, they form salt and water. Therefore, metal hydroxides cannot be used as X in this reaction.
The correct option is (C): Both (1) and (2)