The correct name for the ionic compound CuS is copper(II) sulfide.
Here’s the explanation: In the compound CuS, copper (Cu) has a charge of +2 and sulfur (S) has a charge of -2. Since sulfur typically forms a -2 ion, we can deduce that the copper must be in its +2 oxidation state to balance the overall charge to zero. Therefore, the full name reflects this oxidation state, leading to the name copper(II) sulfide.