Assertion : Compression and rarefaction involve changes in density and pressure. Reason : When particles are compressed, density of medium increases and when they are rarefied, density of medium decreases.

• 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.
• E. If assertion is false but reason is true.