Two charges repel one another. What must be the case?
A.
Either both are positive or both are negative.
B.
The magnitude of their charges must be equal.
C.
neither A nor B
D.
both A and B

Both A and B.

Explanation:

There is a saying, "opposites attract". But, charges with a positive and a positive, or a negative and a negative do not go together. think about magnets. when you put the two magnetic sides together, there is a pull that is away from each other. this means it's of the same charge therefore, they repel.