Well being that there are at least 3 versions of Scott#279Bd and you have confirmed it is type IV, triangle C and horizontal watermark 191 and is orange red (pale) that is a Scott# 279Bd of course only if you can date it between June 1900 and September 1902 when the dark orange red version was issued until January of 1903 when the deep orange red version was issued.
May the force be with you.
