C/D Is the Currency Drain Ratio and R/D Is the Desired

C/D is the currency drain ratio and R/D is the desired reserve ratio. The money multiplier equals

A) $\frac{R / D-C / D}{1+R / D}$ .

B) $\frac{1+C / D}{R / D+C / D}$ .

C) $\frac{1+R / D}{1+C / D}$ .

D) $\frac{R / D+C / D}{1+C / D}$ .

E) $\frac{1+R / D}{R / D+C / D}$ .