Cruz or Carson is fine. Don’t think he is serious about Oprah.
He’s just having fun throwing out Oprah’s name to deflect, since I don’t think he has any intention of naming a VP any time soon.
The election process has a long way to go, and since both men mentioned here are still in the game, Trump is not going to alienate them by making such an announcement. I do think, however, that they would definitely be in his consideration.
Oprah! Now that is a joke.