A

Understanding the motion of a rolling coin:
1. Coin without tilt: When a coin rolls along a plane vertically (without any tilt), all the points of contact between the coin and the plane remain perpendicular to the direction of motion. This configuration maintains the stability of the rolling motion, allowing the coin to move in a straight line due to the uniform transfer of forces along the radius of the coin.
2. Coin with tilt: When the coin is tilted, the center of mass moves at an angle relative to the direction of the plane, resulting in a change in effective weight distribution. As the contact point changes due to the tilt, the forces acting on the rolling coin no longer remain perpendicular to the direction of motion. This creates a tendency to pivot around the base of contact, causing the coin to follow a curved path instead of a straight line.
3. Conclusion: The difference in path is primarily due to the orientation of the coin affecting the gravitational forces acting upon it and its center of mass, which determines stability and trajectory.