Final answer:
The acceleration of a proton at rest at each point is 0 m/s^2.
Step-by-step explanation:
The acceleration of a proton at rest at point a can be found using the formula:
a = q * B / m
Where a is the acceleration, q is the charge of the proton, B is the magnitude of the magnetic field, and m is the mass of the proton.
Since the proton is at rest, its initial velocity is 0 m/s. Therefore, the magnitude of the acceleration is 0 m/s2.
Similarly, at points b, c, and d, since the proton is at rest, the magnitude of the acceleration is also 0 m/s2.