C: drive. - Imouto Style

Onii-chan lives with his 5 younger sisters. Yuzuna, Koume, Karin, Maika, and Mikan. He loves his wonderfully cute younger sisters and enjoys the life he shares with them every day. Unfortunately for their happy home life their parents call from outside the country and ask to live as a family together again.
Since Onii-chan is busy with school they decide to take all his sisters away! It's too much for him to bear so their parents agree to let one sister remain behind with Onii-chan.

Who will Onii-chan choose?