Please explain why e is correct

24. A parallel-plate capacitor is constructed with plates of area A and a gap between the plates d. The capacitor is connected to a battery until the potential difference between the plates is 9V. Then, additional plates are added alongside the original plates, so that now each plate has an area of 3A. The new, expanded capacitor is reconnected to the battery to ensure that the potential difference between the plates is still 9V. At this point, how does the new electric field inside the capacitor compare to the original field? A. The new field is 3x larger than the original B. The new field is 3x smaller than the original C. The new field is 9x larger than the original D. The new field is 9x smaller than the original E. The electric field is unchanged