The U.S. Air Force pays a Turkish citizen $30,000 to work on a U.S. base in Turkey. As a result, a. U.S. government purchases increase by $30,000; U.S. net exports decrease by $30,000; and U.S. GDP is unaffected. b. U.S. government purchases increase by $30,000; U.S. net exports are unaffected; and U.S. GDP increases by $30,000. C. U.S. government purchases, net exports, and GDP are unaffected. d. U.S. government purchases are unaffected; U.S. net exports decrease by $30,000; and U.S. GDP decreases by $30,000.