All are multiple choice questions you can create, but each serves a slightly different purpose.
A POLL is an open question that has no correct answer, whereas a TRIVIA question necessitates a correct answer, which you have to create when you create the object. When a user answers a trivia question, they will immediately know whether or not they got the question right. Meanwhile, a PREDICTION starts in an open state, which means that the user can select any answer. A prediction does not have a correct answer when it is in an "open" state, but once it is closed, users can no longer submit responses, and once you press "complete" on the prediction, it is in its final state and there is then an option for you to select the correct answer to the prediction, which the users then see.