In the iodination of methane, the presence of an oxidizing agent like HIO\(_3\) is required because iodine has a relatively low reactivity. HIO\(_3\) helps facilitate the substitution reaction by oxidizing iodine.
Thus, the correct answer is (C).
Let \( I = \int_{-\frac{\pi}{4}}^{\frac{\pi}{4}} \frac{\tan^2 x}{1+5^x} \, dx \). Then: