Country A (a foreign country that is boycotting Country B, another foreign country) has ordered goods from ABC, a U.S. corporation. Country A has opened a letter of credit with Overseas, Inc., a foreign bank. The letter of credit specifies that ABC must certify that it does not do business with Country B. Overseas, Inc., sends a telegram to First National Bank, a U.S. bank, stating the major terms and conditions of the letter of credit and asking First National Bank to confirm the letter of credit. The telegram does not state the boycott provisions. Overseas mails the letter of credit to First National Bank and asks First National Bank to confirm it. What may First National Bank do?