\[ \begin{array}{ll}a+(-a)=0 \\ \text { A. Additive Inverse } \\ \text { B. Commutative Property of Addition } \\ \text { O } & \text { C. Associative Property of Addition }\end{array} \]

The equation \( a + (-a) = 0 \) illustrates the concept of the additive inverse, which states that for every number, there exists another number that, when added together, results in zero. This principle is foundational in mathematics, ensuring that we can 'cancel out' numbers and return to a neutral state, akin to balancing an equation. In practical terms, the additive inverse is vital in fields like accounting, physics, and computer science. For instance, when balancing financial accounts, expenses (negative values) can be offset by income (positive values) to achieve a balanced budget. Understanding this concept can simplify complex calculations and enhance problem-solving efficiency in everyday life!