Which of the following statements is true?

a. GDP is an important measure of macroeconomic activity because changes in GDP impact employment, incomes, further spending, and standards of living.

b. National income is total income earned by households, whereas personal income is total income received by households.

c. Disposable personal income equals personal income minus personal taxes.

d. The expenditures approach and the income approach yield the same GDP figure.

e. All of the above.