(4) sustainable development Explanation: The gross national product (GNP) measures the welfare of a nation's economy through the aggregate of products and services produced in that nation, Although GNP is a proficient measurement of the magnitude of the economy, many economists, environmentalists and citizens have been arguing the validity of the GNP in respect to measuring welfare. They are calling for a green national product that would indicate if activities benefit or harm the economy and well-being.