I believe the answer is C.

or addition is the mathematical operation of composition that consists of combining or adding two or more numbers to obtain a final or total quantity. The addition also illustrates the process of joining two collections of objects in order to obtain a single collection
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- Whats 2 plus 2?

- Whats 10 plus 10?

- And whats 8 plus 8?

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The two numbers are -4 and -5.