Answer:
c) CuPO₄
Step-by-step explanation:
Copper commonly forms the cation Cu²⁺.
Phosphate is a polyatomic anion which can be represented by PO₄³⁻.
In order to have proper charge balance (an overall charge of 0), there must be three copper cations and two phosphate anions within the compound. As such, the correct ionic formula is Cu₃(PO₄)₂.