How many octaves can each of these singers sing?!

Mariah Carey is a coloratura soprano and has 5-Octave range G#2-G#7 but it's claimed she has close to six octaves!. She would have to sound like Barry White to sing that high and that low!.
beyonce is a Full lyrics Soprano (C3-D6 )with 3 octaves and 2 notes!.
Leona hasn't shown any more than two octaves
kelly clarkson has a 3!.5 octave vocal range!.
There are claims that creditWhitney Houston as having a five-octave vocal range
eva cassidy- 3-octave rangeWww@Enter-QA@Com

---

---

Mariah Carey - 5, close to 6 octaves

Leona Lewis - 3 octaves

Whitney Houston - 5 octavesWww@Enter-QA@Com

---

---