Which of the following statements is true?

a. The most important source of revenue to the federal government is personal income taxes.
b. The most important source of revenue to state governments are sales and property taxes.
c. The most important source of revenue to local governments are local property taxes.
d. The taxation burden, measured by taxes as a percentage of GDP, is lighter in the United States than in most other advanced industrial countries.
e. All of these.

e