Assertion : If a charged particle is moving on a circular path in a perpendicular magnetic field, the momentum of the particle is not changing,. Reason : Velocity of the particle in not changing in the magnetic field.

• 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.