To solve this problem, we need to analyze both statements regarding aniline and its reactions.$\newline$Statement I: Aniline does not undergo Friedel-Crafts alkylation reaction.$\newline$• Friedel-Crafts alkylation requires a Lewis acid catalyst, such as AlCl$_3. \newline$• Aniline contains an amino group $(NH_2)$ which is a strong Lewis base.$\newline$• The amino group coordinates with the Lewis acid, deactivating the catalyst and preventing the reaction.$\newline$• Therefore, aniline does not undergo Friedel-Crafts alkylation.$\newline$Thus, Statement I is correct.$\newline \newline$Statement II: Aniline cannot be prepared through Gabriel synthesis.$\newline$• Gabriel synthesis is used to prepare primary amines from alkyl halides.$\newline$• It involves the use of phthalimide, which reacts with an alkyl halide to form an N-alkylphthalimide.$\newline$• The N-alkylphthalimide is then hydrolyzed to produce a primary amine.$\newline$• However, Gabriel synthesis is not suitable for preparing aryl amines like aniline.$\newline$• This is because aryl halides do not undergo nucleophilic substitution reactions required in Gabriel synthesis.$\newline$Thus, Statement II is correct.$\newline \newline$Both statements are true, so the correct answer is Option 3.