Angular acceleration refers to the rate at which the velocity of a particle moving along a circular path changes with time. It is given by the formula:

Angular acceleration = (change in angular velocity) / (change in time)

Now, let's consider the scenario where a particle is moving along a circular path with uniform speed. In this case, the magnitude of the velocity of the particle remains constant, but its direction continuously changes. This means that the particle is constantly changing its direction of motion, but not its speed.

In a circular motion with uniform speed, the particle moves along the circumference of the circle at a constant rate. This implies that the change in angular velocity over a given time interval is zero. Since the numerator of the angular acceleration formula is zero, the angular acceleration itself will also be zero.

Hence, the correct answer is option 'A' - the angular acceleration of a particle moving along a circular path with uniform speed is zero.

To summarize:

- When a particle moves along a circular path with uniform speed, its angular acceleration is zero.
- Angular acceleration is the rate at which the velocity of a particle changes with time.
- In circular motion with uniform speed, the particle's speed remains constant, but its direction continuously changes.
- Since the particle's speed does not change, the change in angular velocity over a given time interval is zero.
- Therefore, the angular acceleration in this case is zero.