Bank Draft:
A bank draft is a payment instrument that guarantees the payment of a specified amount of money to the recipient. It is issued by banks on behalf of their customers and is considered a secure method of payment.

Issuers of Bank Draft:
A bank draft can be issued by various types of banks. These include:

- Private Sector Banks: Private sector banks are financial institutions that are owned and operated by private individuals or corporations. These banks issue bank drafts as a service to their customers, allowing them to make secure payments.

- Regional Rural Banks: Regional rural banks (RRBs) are financial institutions that are established in rural areas to provide banking services to the rural population. RRBs also issue bank drafts to facilitate secure transactions for their customers.

- Public Sector Banks: Public sector banks are banks that are owned and operated by the government. These banks, being major players in the banking industry, also issue bank drafts to their customers.

Reason for Correct Answer:
The correct answer to this question is option 'D' - All of the above. This is because all three types of banks mentioned (private sector banks, regional rural banks, and public sector banks) have the authority and capability to issue bank drafts. They provide this service to their customers to facilitate secure and convenient transactions.

Conclusion:
Bank drafts are issued by different types of banks, including private sector banks, regional rural banks, and public sector banks. These banks offer this service to their customers to ensure secure payments. Therefore, the correct answer to the question is option 'D' - All of the above.