Reserves increase if the Federal Reserve lowers the discount rate or auctions more credit.
Option C
Explanation:
Unless the Federal Reserve raises liquidity, a single bank may lend its bank reserves to the degree that it produces equivalent deposits. Nevertheless, the banking sector can raise deposits multiple times.
When each bank invests and generates a loan, it reduces reserves for other banks that use it to raise its liquidity and thus create new deposits, until all existing reserves are being used.
When it has to hold $100 as reserve balances against the investment it makes concurrently it loses reserve sums of $1,000, the most a lender can lend is $900.