Four charges $2\mu\text{C}, -3\mu\text{C}, 4\mu\text{C}, -4\mu\text{C}$ and $-1\mu\text{C}$ are enclosed by the Gaussian surface of radius $2\text{ m}$ . Net outward flux through the Gaussian surface is (in $\mu\text{V} - \text{m}$ ) [ $\epsilon_0 =$ permittivity of free space]}