Indicate whether each of the following items represents a credit or a debit on the U.S. balance of payments.
a. A U.S. importer purchases a shipload of French wine.
b. A Japanese automobile firm builds an assembly plant in Kentucky.
c. A U.S. college student spends a year studying in Switzerland.
d. American charities donate food to people in drought-plagued Africa.
e. Japanese investors collect interest income on their holdings of U.S. government securities.
f. A German resident sends money to her relatives in the United States.