Assertion : tert-Butyl methyl ether reacts with $\mathrm{HBr}$ to form tert-butyl bromide and methanol. Reason : It follows $\mathrm{S}_{\mathrm{N}} 1$ mechanism.

• 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'.