Which of the following statements is true about the magnitude of the electric field in the transition region of an NP junction? A. It is constant in space. B. It increases linearly from the N side to the P-side. C. It decreases linearly from the N side to the P-side. D. It first increases linearly, reaches a peak at the junction, then decreases linearly. E. It increases quadratically from the N side to the P-side.