Which of the following ionic substances will be most effective in precipitating the sulphur sol?

• A

  $\mathrm{KCl}$
• B

  $\mathrm{BaCl}_{2}$
• Correct answer
  C

  $\mathrm{Fe}_{2}\left(\mathrm{SO}_{4}\right)_{3}$
• D

  $\mathrm{Na}_{3} \mathrm{PO}_{4}$

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