A particle of mass m is made to move with uniform speed v along the perimeter of a regular polygon of n sides, inscribed in a circle of radius a. The magnitude of impulse applied at each comer of the polygon is :

• A. \[2mv\sin \frac{\pi }{n}\]  
• B. \[mv\sin \frac{\pi }{n}\]
• C. \[mv\sin \frac{n}{\pi }\]  
• D. \[mv\sin \frac{n}{\pi }\]