Which of the following is a means of payment?

A means of payment is a document or instrument that can be used directly to settle a debt or transfer money. A postal order is bought from the post office for a specific amount and can be cashed or paid into an account by the person named on it, making it a direct method of paying someone, especially useful for sending money by post.

The other items are not means of payment in themselves. C.I.F (Cost, Insurance, and Freight) is a shipping term that states who bears the cost and risk for goods during transport in international trade; it is a term describing trade conditions, not a payment instrument. An I.O.U is simply an informal written acknowledgement that money is owed; it does not transfer money and cannot be used to settle a debt with a third party. A promissory note is a written promise to pay a sum of money at a future date, so it represents a deferred obligation rather than an immediate means of payment.

Examination reminder: a true means of payment must be usable right away to move money or settle a debt; a mere promise or acknowledgement of debt does not qualify.