15. The marginal propensity of saving in Country A is 0.5. Currently, the country is suffered from
COVID-19 and the government gives 3000 local dollars to every national. Suppose due to this policy,
each national can help to increase money supply 2000 local dollars through the fractional-reserve
banking system. What is the reserve ratio for Country A?
(A) 20%
(B) 30%
(C)40%
(D) 50%