Which among the following statements is true about the reactivity of haloarenes towards nucleophilic substitution reactions?
$1$. Haloarenes are very reactive towards nucleophilic substitution reaction.
$2$. In haloarenes,the $C-X$ bond acquires partial double bond character.
$3$. The $C-X$ bond in haloarenes is longer than the $C-X$ bond in haloalkanes.
$4$. In haloarenes,the phenyl cation formed as a result of self-ionisation is stable.

• A
  $1$
• B
  $2$
• C
  $3$
• D
  $4$