Meaning of Bill of ?ExchangeAccording to the Negotiable Instruments Act 1881, a bill of exchange is defined as œan instrument in writing containing an unconditional order, signed by the maker, directing a certain person to pay a certain sum of money only to, or to the order of a certain person or to the bearer of the instrument. Some of the characteristics of the Bill of Exchange:It is important to have a bill of exchange in writing. It must contain a confirmed and unconditional order to make a payment and not just the request. The order should not have any condition. The bill of exchange amount should be definite. Fixed date for the amount to be paid. The bill must be signed by both the drawee and the drawer. The amount stated on the bill should be paid on-demand or on the expiry of a fixed time. The amount is paid to the beneficiary of the bill, specific person, or against a definite order. Therefore, in the above question option no. 3 i. e. The promise to pay must always be conditional, is incorrect.