A Pink appeared on SBS PowerFM's 'Kim Chang Ryul's Old School' on October 18 and talked about their concept and latest song.  

The girls have done the innocent concept their whole career.  About this, Eunji said, "If we discard that concept, it'll feel like we're retiring."  Hearing this, DJ Kim Chang Ryul gently argued, "Eunji's solo album gave off Eunji's vibe rather than A Pink's, so that was nice. There is the innocent concept, but I think it'd also be good if you did other things, too."

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Regarding the new song, the DJ brought up the fact that all members cried when they first heard their title song, "Only One."  Eunji said, "We were doing our concert in Japan at the time.  Our comeback had been pushed back because the title song had not been decided on, but then we listened to that song.  Finally, we'd be able to promote [as a whole group], so we cried out of happiness."