If the fed purchases securities worth $10 million from a commercial bank, the banking system's balance sheet will show a. an increase in securities held of $10 million and a decrease in bank reserves of $10 million. b. a decrease in securities held of $10 million and an increase in bank reserves of $10 million. c. a decrease in securities held of $10 million and a decrease in bank reserves of $10 million. d. an increase in securities held of $10 million and an increase in bank reserves of $10 million.