Answer
We can rank the protons according to the magnitude of their accelerations due to the field, as follows:
$a = b = c = d = e$
Work Step by Step
We can write the equation for the force on a charge due to an electric field:
$F = q~E$
Note that the force does not depend on a particle's velocity.
We can find an expression for the magnitude of the acceleration of a particle in a uniform electric field:
$F = ma$
$q~E = ma$
$a = \frac{q~E}{m}$
The magnitude of the acceleration is the same for all the protons in the electric field since the electric field is uniform, and the protons all have the same charge and mass.
We can rank the protons according to the magnitude of their accelerations due to the field, as follows:
$a = b = c = d = e$
