To solve this problem, we need to find the mobility of a charged particle.$\\$Mobility $(\mu)$ is defined as the drift velocity per unit electric field.$\\$The formula for mobility is:$\\ \mu = \frac{v_d}{E} \\$where:$\\$• $v_d$ is the drift velocity of the particle.$\\$• $E$ is the electric field.$\\$Given:$\\ v_d = 7.5 \times 10^{-4}$ m/s$\\ E = 3 \times 10^{-10}$ V/m$\\$Substitute the given values into the formula:$\\ \mu = \frac{7.5 \times 10^{-4}}{3 \times 10^{-10}} \\$Simplify the expression:$\\ \mu = \frac{7.5}{3} \times \frac{10^{-4}}{10^{-10}} \\ \mu = 2.5 \times 10^{6} \\$Therefore, the mobility of the charged particle is $2.5 \times 10^{6}$ m$^2$ V$^{-1}$ s$^{-1}. \\$This corresponds to Option 1.