When 100 mL of 0.2 M solution of $\mathrm{CoCl}_3 \cdot x \mathrm{NH}_3$ is treated with excess of $\mathrm{AgNO}_3$ solution, $3.6 \times 10^{22}$ ions are precipitated. The value of $x$ is $\left(\mathrm{N}=6 \times 10^{23} \mathrm{~mol}^{-1}\right)$

• A

  $5$
• Correct answer
  B

  $6$
• C

  $4$
• D

  $3$

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