Is theism true?

And if so, which of the many brands is the true one?

Do the three Abrahamic religions make the same doctrinal claims or do they differ sufficiently to be contradictory?

Is Scientology a separate theism? Should we consider it as true? Or is Mormonism the true theism?

And how is one to know which of the competing denomination is the truth?

Can one be forgiven for not believing in any of them until such a time as their claims can be verified? That is, is it rational to not believe in any of the available theism-s?

Are deists a separate theism or do their claims suffer from the weaknesses of the other theism-s?