To solve this problem, we need to find the permeability of the material of the rod.$\\$Given:$\\$• Magnetic susceptibility $\chi_m = 599 \\$• Magnetizing field $H = 1200 \, \mathrm{A/m} \\$• Permeability of free space $\mu_0 = 4\pi \times 10^{-7} \, \mathrm{Tm/A} \\$The relationship between permeability $\mu,$ susceptibility $\chi_m,$ and $\mu_0$ is given by:$\\ \mu = \mu_0 (1 + \chi_m) \\$Substitute the given values:$\\ \mu = 4\pi \times 10^{-7} \times (1 + 599) \\$Simplify the expression:$\\ \mu = 4\pi \times 10^{-7} \times 600 \\ \mu = 2400\pi \times 10^{-7} \\ \mu = 2.4\pi \times 10^{-4} \, \mathrm{Tm/A} \\$Therefore, the permeability of the material of the rod is $2.4\pi \times 10^{-4} \, \mathrm{Tm/A}. \\$This corresponds to Option 4.