The correct answer is A) the direction of motor rotation will remain the same. Reversing both the field and armature connections of a DC propulsion motor will not change the direction of rotation. This is because the armature and field currents are both reversed, which maintains the same relative polarity between the field and armature. As a result, the direction of the torque developed, and thus the direction of rotation, remains unchanged. The other options are incorrect because reversing both connections does not lead to overheated brushes (C) or a magnetic lock in the motor (D). The direction of rotation would only change if either the field or armature connections were reversed, but not both (B).