Assertion : $\mathrm{O}_2 \mathrm{~F}_2$ converts $\mathrm{Pu}$ to $\mathrm{PuF}_6$. Reason : $\mathrm{O}_2 \mathrm{~F}_2$ is used to remove unreacted $\mathrm{Pu}$ from nuclear reaction.

• Correct answer
  A

  If both assertion and reason are true and reason is the correct explanation of assertion.
• B

  If both assertion and reason are true but reason is not the correct explanation of assertion.
• C

  If assertion is true but reason is false.
• D

  If both assertion and reason are false.

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