If the banks in an economy operate with a reserve ratio of 20 percent then the money multiplier is ?

A. a regional area within which trade with foreign nations is allowed
B. a free trade agreement among several nations
C. designed to limit exports of manufactured goods by placing export taxes on goods made within the zone
D. designed to promote exports by deferring imports duties on intermediate inputs and waving such duties if the final product is re-exported rather than sold domestically