To solve this problem, we need to calculate the magnetic energy stored in an inductor.$\\$The formula for the energy $(U)$ stored in an inductor is given by:$\\ U = \frac{1}{2} L I^2 \\$where:$\\$• $L$ is the inductance of the inductor.$\\$• $I$ is the current flowing through the inductor.$\\$Given:$\\ L = 4 \mu H = 4 \times 10^{-6} H \\ I = 2 A \\$Substitute the given values into the formula:$\\ U = \frac{1}{2} \times 4 \times 10^{-6} \times (2)^2 \\$Calculate $I^2: \\ I^2 = 2^2 = 4 \\$Substitute $I^2$ back into the equation:$\\ U = \frac{1}{2} \times 4 \times 10^{-6} \times 4 \\$Simplify the expression:$\\ U = 2 \times 4 \times 10^{-6} \\ U = 8 \times 10^{-6} \\$Convert $8 \times 10^{-6}$ to $\mu J: \\ U = 8 \mu J \\$Therefore, the magnetic energy stored in the inductor is $8 \mu J. \\$This corresponds to Option 4.