_______________ are the amount of funds that a depository institution must hold in reserve against specified deposit liabilities.

The correct choice identifies reserve requirements as the funds that a depository institution is mandated to keep in reserve against its specified deposit liabilities. These reserve requirements are essential for ensuring the stability and liquidity of the banking system. By having a certain percentage of deposits set aside, banks can meet withdrawal demands from customers and maintain the overall health of the financial system.

This concept is crucial in banking regulation and monetary policy, as it helps central banks control the money supply and influence interest rates. By adjusting reserve requirements, regulators can either encourage lending by lowering the amount banks must hold in reserve or restrict it by increasing those requirements.

The other options do not represent this specific concept. The FDIC, for example, refers to the Federal Deposit Insurance Corporation, which insures deposits, but it does not pertain directly to the funds that banks must hold. Discount requirements are not a standard term in banking and do not relate directly to the reserve funds held by institutions. Therefore, identifying reserve requirements as the proper definition helps underline the importance of liquidity management in the banking sector.