Assertion: A small amount of acid or alkali is added before electrolysis of water. Reason: Pure water is weak electrolyte. Read the assertion and reason carefully to mark the correct option out of the options given below:

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