Neither of those 4!
New hint: You're looking at the teeth of an SKE girl~!
Guesses so far:
- Oshima Yuko
- Sugamoto Yuko
- Nakagawa Haruka
- Oota Aika
- Masuda Yuka
- Ishida Haruka
- Nito Moeno
- Yokoyama Yui
- Kitahara Rie
- Hirajima Natsumi
- Yamamoto Sayaka
- Sato Amina
Hints so far:
- Not old (pre-Budoukan shuffle) Team B
- Not old Team K