Which one of the following is the CORRECTexpression for voltmeter sensitivity of PMMC type instrument?

A

$$\frac{R_{m}+R_{s}}{V}$$

B

$$\frac{R_{m} R_{s}}{V}$$

C

$$\frac{R_{m}+R_{s}}{V^{2}}$$

D

$$\frac{R_{m} R_{s}}{V^{2}}$$