Assertion : Keber's organ in Unio is situated in front of the pericardium. Reason : Keber's organ has an important role in circulation.

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