Answer:
C. Plate A is negatively charged and plate B is positively charged.
Explanation:
The direction of the lines of an electric field represents the direction to which a positive test charge placed in that field would move. Therefore, since positive charges are repelled by positive charges and attracted by negative charges, this means that:
- Electric field lines point away from positive charges, and
- Electric field lines point towards negative charges
In the figure in the problem, we see that electric field lines go away from plate B and towards plate A. This means that:
- Plate B is positively charged
- Plate A is negatively charged