Under which of the following situations might dollar-denominated debt become a problem? O A. When issued by the U.S., but the dollar has generally appreciated at payback time. O B. When issued by the U.S., but the dollar has generally depreciated at payback time. O C. When issued by a country other than the U.S., but whose currency has depreciated against the dollar at payback time. O D. When issued by a country other than the U.S., but whose currency has appreciated against the dollar at payback time