I voted for waist. I want it that long because I want longer hair than my sister. My sister has 4a waist length hair as a child and as an adult she has BSL. I think she keeps it cut so it is not longer than BSL for maintenance. She relaxes, colors, and she does not belong to any hair boards, and she still has long hair. I even witness her go from BSL to nape (when some so-called friend cut my sister's hair) back to BSL.
My grandmother had almost BSL when she passed. I believe she had longer hair when she was younger. Several of my aunts and cousins had APL or longer hair at one point in their life and I want to join them.
So sibling rivalry is my M.O. for wanting long hair.