The answer is B.
Opposite charges attract to each other. Alike charges repel each other. We’ve been taught this since elementary school. So, charges determine the electrical force.
Newton’s Law of Gravity essentially says the gravitational force is reliant on the mass of the two bodies and the distance squared between them.
To debunk answer A, you could think of magnets. Then compare that system to something like idk, a set of balls that are smaller than the magnets. According to A, the gravity between the balls would be from the electrical force which is beyond incorrect. And the force between the magnets is from gravity, which is also incorrect. Size doesn’t matter