The Net National Product (NNP) is Gross National Product (GNP) less

The Net National Product (NNP) is the Gross National Product (GNP) minus the depreciation of capital during a specific period. GNP is the total value of goods and services produced by the nationals of a country, either inside or outside the country's borders, within a particular period. In contrast, NNP is the total income earned by the nationals of a country, including depreciation, within the same period. Depreciation refers to the wear and tear of capital goods such as machinery, equipment, and buildings used in production during a specific period. Since capital goods depreciate over time, their value decreases as they are used. Thus, depreciation represents the reduction in the value of capital during a particular period. Therefore, the correct option is "depreciation."