[Cedille]

I suppose these reading is provided by the official party, since there are many sites saying "Hana" is correct (and Hana also appears in the lyric section).

http://www.amazon.co.jp/%E7%B4%8B-%E.../dp/B005I063DU
http://music.goo.ne.jp/lyric/LYRUTND120024/index.html
http://www.uta-net.com/song/121451/
http://www.starchild.co.jp/artist/ha...111029_30.html