Among the given options, Postal order is a means of payment.
A postal order is a financial instrument issued by the post office for the transfer of a specific sum of money from one person to another. It is a type of payment method that allows individuals to send money through the postal service. The sender purchases the postal order from the post office and fills in the name of the recipient, who can then cash it in at their own post office. This method is commonly used for small transactions, such as sending money to family and friends, or for online purchases where other forms of payment may not be accepted.