(a) To the same class, the salary rate received at the time of separation adjusted for the salary range changes for the class since the separation.

(b) To another class with substantially the same salary range as the class from which separated, the salary rate may be either the same salary rate the employee would receive if appointed to such former class or the rate in the salary range which does not exceed the total number of range differentials above or below the rate the employee would receive if appointed to such former class.

(c) To a different class which has a lower salary range than the class from which separated, a salary rate not to exceed the salary rate last received in the class from which separated, adjusted for the salary range changes of the latter class since separation.