Recurring Deposits (RD) are a type of savings scheme offered by banks and financial institutions. They allow individuals to deposit a fixed sum of money every month for a predetermined period, typically ranging from 6 months to 10 years. RDs are popular among individuals who want to save a specific amount of money over time and earn interest on their savings.

a) Fixed Monthly Deposits:
In a recurring deposit, a fixed sum is deposited every month by the account holder. This amount can be determined by the individual based on their financial capacity and savings goals. The monthly deposit remains the same throughout the tenure of the RD.

b) Fixed Tenure:
The period of deposit in a recurring deposit is a fixed tenure. This means that the account holder chooses a specific duration for which they want to deposit money regularly. This tenure can vary depending on the terms and conditions set by the bank or financial institution. Once the tenure is chosen, it cannot be changed unless the account is prematurely closed.

c) Interest at FDR Rates:
Interest is paid on the recurring deposit at Fixed Deposit Rates (FDR). Fixed Deposit Rates are the interest rates offered on fixed deposit schemes by banks and financial institutions. These rates are predetermined and may vary from one bank to another. The interest earned on the recurring deposit is added to the account holder's savings at the end of the tenure.

d) All of the Above:
The correct answer is option 'D' - All of the above. This is because all the statements mentioned in options a, b, and c are true for recurring deposits. In RDs, a fixed sum is deposited every month, the period of deposit is a fixed tenure, and interest is paid at FDR rates. Therefore, option 'D' encompasses all the key features of recurring deposits.