Chuck got 38-C and palmed Hibiki's ball nervously.  He wasn't sure if he should open with her, or Ariel.  He knew he definitely didn't want to open with Papyrus, Cosmo, Jotaro or Omega, since the former two were ultra beasts, and insanely powerful, and the latter two were incredibly rare.  He was hesitant to use Hibiki, since she was quite powerful herself, at the same time they had formed a strong bond between the two of them over the last week of training.