There Is $5,000,000 of Currency in Econland, All Held by Banks

There is $5,000,000 of currency in Econland, all held by banks as reserves.The public does not hold any currency.If the banks'desired reserve/deposit ratio is 0.25, then the money supply equals:

A) $5,000,000
B) $6,250,000
C) $10,000,000
D) $20,000,000