To find the resistance of a galvanometer by the half deflection method the following circuit is used with resistances $$R_1 = 9970$$ W, $$R_2 = 30$$ W and $$R_3 = 0$$. The deflection in the galvanometer is d. With $$R_3 = 107$$ W the deflection changed to $$\frac{d}{2}$$. The galvanometer resistance is approximately:

A

107$$\Omega$$

B

137$$\Omega$$

C

107/2$$\Omega$$

D

77$$\Omega$$