(a) The cashier, treasurer, or managing official of a corporation shall make the affidavit required to authenticate a claim of the corporation.
(b) In an affidavit made by an officer of a corporation, or by an executor, administrator, guardian, trustee, assignee, agent, or attorney, it is sufficient to state that the affiant has made diligent inquiry and examination and believes the claim is just and that all legal offsets, payments, and credits made known to the affiant have been allowed.