Among the following, the surfactant that will form micelles in aqueous solution at the lowest molar concentration at ambient conditions is

• Correct answer
  A

  $\mathrm{CH}_3\left(\mathrm{CH}_2\right)_{15} \mathrm{~N}^{+}\left(\mathrm{CH}_3\right)_3 \mathrm{Br}^{-}$
• B

  $\mathrm{CH}_3\left(\mathrm{CH}_2\right)_{11} \mathrm{OSO}_3^{-} \mathrm{Na}^{+}$
• C

  $\mathrm{CH}_3\left(\mathrm{CH}_2\right)_6 \mathrm{COO}^{-} \mathrm{Na}^{+}$
• D

  $\mathrm{CH}_3\left(\mathrm{CH}_2\right)_{11} \mathrm{~N}^{+}\left(\mathrm{CH}_3\right)_3 \mathrm{Br}^{-}$

Hence, the correct answer is option: 'A'.