The conducting spherical shells shown in the figure are connected by a conductor. The capacitance of the system is

$4\pi\epsilon_0 \frac{ab}{b-a}$ $4\pi\epsilon_0 a$ $4\pi\epsilon_0 b$ $4\pi\epsilon_0 \frac{b^2}{b-a}$

$4\pi\epsilon_0 b$

$\text{Since the two conductors are connected hence the capacitance of the system is the capacitance due to outer sphere of radius b.}$                         $ \Rightarrow C = 4\pi \epsilon_0 b$