In the given reaction:
\[
\text{CuSO}_4 + \text{Fe} \rightarrow \text{FeSO}_4 + \text{Cu}
\]
Iron (Fe) displaces copper (Cu) from copper sulfate (CuSO$_4$), forming iron sulfate (FeSO$_4$) and copper metal. Since a more reactive metal (iron) replaces a less reactive metal (copper) in a compound, this is classified as a single displacement reaction.