Which of the following isomers has the highest boiling point?

Nitrobenzene on reduction using zinc in alkaline medium results in $X$. The number of $\sigma$ and $\pi$ bonds in $X$ is

Given below are two statements:
Statement $I$: Aniline does not undergo Friedel-Crafts alkylation reaction.
Statement $II$: Aniline cannot be prepared through Gabriel synthesis.
In the light of the above statements,choose the correct answer from the options given below:

In the following chemical reaction,
$CH_3CH_2NH_2 + CHCl_3 + 3KOH \rightarrow (a) + (b) + 3H_2O$
What are the products $(a)$ and $(b)$ respectively?

Aniline on treatment with a mixture of conc. $HNO_3$ and conc. $H_2SO_4$ yields:

The order of basic strength of methyl substituted amines and $NH_3$ in aqueous solution is