Which of the following statements is CORRECT?
a) The U.S. net international investment position is defined as the value of U.S. assets less the value of U.S. liabilities.
b) The U.S. net international investment position is usually negative, but it was positive at the end of 2022 because of higher prices of foreign wealth.
c) The U.S. net international investment position was positive at the end of 2022 as the U.S. businesses invest heavily abroad in that year.
d) All of the above statements are correct.