Indicate how each of the following international transactions is entered into the U.S. balance of payments with double-entry bookkeeping:
(a) A U.S. resident imports $500 worth of merchandise from a U.K. resident and agrees to pay in three months.
(b) After the three months, the U.S. resident pays for his imports by drawing down his bank balances in London.
(c) What is the net effect of transactions (a) and (b) on the U.S. balance of payments if they occur during the same year?