(1) A joint account belongs, during the lifetime of all parties, to the parties in proportion to the net contributions by each to the sums on deposit, unless there is clear and convincing evidence of a different intent.
(2) A P.O.D. account belongs to the original payee during his lifetime and not to the P.O.D. payee or payees; if two or more parties are named as original payees, during their lifetimes rights as between them are governed by subsection (1) of this section.
(3) Unless a contrary intent is manifested by the terms of the account or the deposit agreement or there is other clear and convincing evidence of an irrevocable trust, a trust account belongs beneficially to the trustee during his lifetime, and if two or more parties are named as trustee on the account, during their lifetimes beneficial rights as between them are governed by this section. If there is an irrevocable trust, the account belongs beneficially to the beneficiary.