A legal tender is a form of payment recognized by law as valid for meeting a financial obligation. In simple terms, it is a currency that must be accepted if offered in payment of a debt.
Of the options listed, only bank notes are considered legal tender. Bank notes are issued by a country's central bank and are generally accepted as a form of payment for goods and services.
Cheques, travellers cheques, and goldsmith receipts are not considered legal tender. Cheques and travellers cheques are a type of negotiable instrument that allow for the transfer of funds from one bank account to another, but they are not considered legal tender. Goldsmith receipts are a type of certificate that represents ownership of a specific amount of gold, but they are not widely accepted as a form of payment and are not considered legal tender.