You may choose just the first mode (targeting a creature spell), just the second mode (targeting a creature card in your graveyard), or both modes (targeting a creature spell and a creature card in your graveyard). You can't choose a mode unless there's a legal target for it.

If you choose both modes, you choose their targets at the same time. You can't counter your own creature spell and then return that card from your graveyard to your hand.