(a)a security, created and issued, [by the Government] [Substitued for the words whether before or after the commencement of this Act, by the Central Government or a State Government by the Public Debt (Amendment) Act, 1956 (57 of 1956), Section 5 (15-10-1956)] for the purpose of raising a public loan, and having one of the following forms, namely:--(i)stock transferable by registration in the books of the Bank; or(ii)a promissory note payable to order; or(iii)a bearer bond payable to bearer; or(iv)a form prescribed in this behalf;