Paper Money was invented in China. a. The first notes were silver certificates issued by merchants. b. The first notes were "flying cash"- deposit receipts for bronze coins deposited in certain cities. c. The first notes were "ready cash" - deposit receipts for silver issued by the central bank in Bejing. d. The first notes were deposit receipts issued by regulated merchants for strings of cash. e. The first notes were issued by the state during the Ming dynasty. f. Other, specify