Three baby hearts is good opposite partner s shortness, as well as the spade ace. I can t believe partner can have a hand that will go down. 4C seems pretty wishy-washy. It shows some interest, but essentially tells partner that you refuse to make the decision. This has to be the time to give him a clear, simple answer.
Second choice is pass.
3S. This is certainly a cuebid with clubs as trump. You can t be showing spade length, because you would have bid 2S last round. Therefore, this has to show the spade ace, looking for a heart control for 6C . Keep in mind that partner is probably suspicious this hand is a misfit, and if you do anything other than bid clubs now, he ll probably keep thinking that. Maybe he ll convince himself that you re trying to show a 6-card suit that was too weak to insist on the last round, or that you re making some exotic try for notrump.