(B) Both spheres are at the same potential,so $V_1 = V_2$.
Using the formula for potential $V = \frac{kq}{R}$,we have $\frac{kq_1}{R_1} = \frac{kq_2}{R_2}$.
Since the charge $q = \sigma A = \sigma (4\pi R^2)$,we substitute this into the potential equation:
$\frac{k(\sigma_1 4\pi R_1^2)}{R_1} = \frac{k(\sigma_2 4\pi R_2^2)}{R_2}$.
Simplifying this,we get $\sigma_1 R_1 = \sigma_2 R_2$.
Therefore,the ratio of surface charge densities is $\frac{\sigma_1}{\sigma_2} = \frac{R_2}{R_1}$.
Since $R_1 > R_2$,it follows that $\frac{R_2}{R_1} < 1$,which implies $\sigma_1 < \sigma_2$.
Thus,the charge density of the smaller sphere $(R_2)$ is greater than the charge density of the larger sphere $(R_1)$.