Answer:
option C
Explanation:
The correct answer is option C.
The normal force is the force exerted by the biker on the inner vertical surface of the circular track.
When the biker move in the circular track centripetal force is acting on the biker which is being balanced by the normal force.
To overcome the gravitation force on the biker the velocity of the biker should be high such that centripetal acceleration of the biker can overcome the gravity force acting on the biker.
