If Banks Have Zero Excess Reserves,then the Net Effect of Any

If banks have zero excess reserves,then the net effect of any check writing and depositing on the money supply is

A) positive since the required reserve ratio is less than one.
B) positive as long as no one takes cash out of the system.
C) zero,since the gain in excess reserves at one bank are exactly offset by a reduction in excess reserves at another bank.
D) negative since one bank loses more in total reserves than the other bank gets in excess reserves.