The true statement about electrical charges is:
Two positive charges repel each other.
Here’s a brief explanation of the other statements:
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When a combination of negative and positive charges are present, the charges of opposite signs repel one another. (This statement is false; opposite charges attract each other.)
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Two negative charges attract each other. (This statement is false; two negative charges repel each other.)
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Two positive charges attract each other. (This statement is also false; two positive charges repel each other.)
So, the correct response is the first one: "Two positive charges repel each other."