A cubic box of side $a,$ oriented as shown, contains an unknown total charge. The vertically directed electric field has a uniform magnitude $E$ pointing upwards on the top surface and $3E$ pointing downward on the bottom surface, as shown in the figure.

How much charge $Q$ is inside the box?

$Q_{\text{e}\text{n}\text{c}\text{l}}=2\frac{E}{lo{n}_0{a}^2}$

$Q_{\text{e}\text{n}\text{c}\text{l}}=4lo{n}_{0}E{a}^2$

$Q_{\text{e}\text{n}\text{c}\text{l}}=3lo{n}_{0}E{a}^2$

$Q_{\text{e}\text{n}\text{c}\text{l}}=\frac{1}{2}lo{n}_{0}E{a}^2$

$Q_{\text{e}\text{n}\text{c}\text{l}}=6lo{n}_{0}E{a}^2$

$Q_{\text{e}\text{n}\text{c}\text{l}}=3\frac{E}{lo{n}_0{a}^2}$

$Q_{\text{e}\text{n}\text{c}\text{l}}=\frac{E}{lo{n}_0{a}^2}$

$Q_{\text{e}\text{n}\text{c}\text{l}}=0$

$Q_{\text{e}\text{n}\text{c}\text{l}}=2lo{n}_{0}E{a}^2$

insufficient information