Which of the following statements about GDP is correct?

A、GDP measures two things at once: the total income of everyone in the economy and the total expenditure on the economy’s output of goods and services.;
B、Money continuously flows from households to firms and then back to households, and GDP measures this flow of money.;
C、GDP is generally regarded as the best single measure of a society’s economic well­being.;
D、GDP measures two things at once: the total income of everyone in the economy and the unemployment rate of the economy’s labor force.