could you please explain option (c) and (d)?

Self-Assessment Questions Which of the following will give rise to a higher increase in money supply given the same increase in monetary base? A. An increase in desired reserve ratio by the commercial banks . A decrease in desired reserve ratio by the commercial banks C. An increase in currency holding by the general public before they redeposit their receipt. D. A decrease in required reserve ratio when the commercial banks generally voluntarily hold excess reserve