You need to analyse what conditions make it possible for a murderer to become a saint within one lifetime. The third type of question is one where it is necessary to ask a counter question to help the questioner to think through. The fourth kind of question is one that should be dropped. It means that you should not answer it. These are the questions which are speculative in nature, and any answer to such questions will only create ore confusion.
People can discuss such questions for years without coming to a conclusion.
They can only answer such questions based on their imagination, not on real understanding. Some answers which the Buddha gave have close parallels to the kind responses which are given in nuclear science. It is important to note however that the Buddha did give answers to some of these questions to His most intellectually developed disciples after the questioner had left. And in many cases, His explanations are contained in other discourses which show us, who live in an age of greater scientific knowledge, why these questions were not answered by the Buddha just to satisfy the inquisitive minds of the questioners.