Why are economists concerned with GDP?

Gross domestic product tracks the health of a country's economy. It represents the value of all goods and services produced over a specific time period within a country's borders.

Explanation:

Economists can use GDP to determine whether an economy is growing or experiencing a recession.

GDP measures the total market value (gross) of all U.S. (domestic) goods and services produced (product) in a given year. When compared with prior periods, GDP tells us whether the economy is expanding by producing more goods and services, or contracting due to less output.

rosevelt. 1973. "slaves everywhere"

i would say your answer is a)

sorry if im wrong