d
Net electric flux ( \(\phi_{\text {Net }}\) ) through the cubic surface is given by

\(\phi_{N e t}=\frac{q}{\varepsilon_{0}}\)

Where, \(\varepsilon_{0}=\) Permittivity of free space \(=8.854 \times 10^{-12}\, N ^{-1} \,C ^{2}\, m ^{-2}\)

\(q =\) Net charge contained inside the cube \(=2.0\, \mu \,C =2 \times 10^{-6} \,C\)

\(=2.26 \times 10^{5} \,N \,m ^{2} \,C ^{-1}\)

\(\therefore \phi_{N e t}=\frac{2 \times 10^{-6}}{8.854 \times 10^{-12}}\)

The net electric flux through the surface is \(2.26 \times 10^{5} \;N \;m ^{2} \,C ^{-1}\)