How many of the statement(s) are correct
i) The nucleophile makes a rear attack in ${\text{S}}_{\text{N}}\text{2}$ reaction and expels the leaving group from front side.
ii) $\mathrm{C}{\mathrm{H}}_3\mathrm{O}-\mathrm{C}\mathrm{H}=\mathrm{C}{\mathrm{H}}_2$ adds to $\text{HBr}$ according to Anti‐Markownikoff’s rule.
iii) The basicity of halides decreases in the order ${\mathrm{F}}^{-}>\mathrm{C}{1}^{-}>\mathrm{B}{\mathrm{r}}^{-}>{\mathrm{I}}^{-},$ but the nucleophillicity is reverse of it. (in polar protic solvents)
iv) The rate of ${\text{S}}_{\text{N}}\text{2}$ reaction is independent of the polarity of the solvent.
v) Sigma complex or arenium ion is resonance stablised.

Hence, the correct answer is 3.