Final answer:
The statement about GDP that is most accurate is option b: If a business firm is polluting, GDP captures the value of the firm's output but not the harm caused by dirtier air.
Step-by-step explanation:
The most accurate statement about GDP is option b: If a business firm is polluting, GDP captures the value of the firm's output but not the harm caused by dirtier air. GDP is a measure of the value of all final goods and services produced within a country in a year, and it does not take into account externalities such as pollution. Therefore, GDP can capture the economic value of a firm's output without considering the negative impact on the environment or public health. For a more comprehensive measure of economic welfare, other indicators such as the Genuine Progress Indicator (GPI) or the Human Development Index (HDI) are used.