Which is the correct answer? Please show the calculations you used

9. There is monetary equilibrium in the economy. The total currency in the economy is $6 million, of which the public holds $4 million. The commercial banks' deposits at the Central Bank are $4 million and the money supply is $34 million. What is the reserve ratio of the commercial banks? A) 0.10. B) 0.15. C) 0.20. D) 0.25. E) None of the above