I'm inclined to agree with Dottie--her giftedness will let her blend in the new grade level gifted classes so option B seems fine. And I'll add (from my own experience of this same skip two and a bit decades ago) that being eased into non-gifted classes after a grade skip was actually detrimental because the new peer group's social and academic norms were distinctly different from those of the gifted group I was used to and they were less than pleased to have a younger hand-waving-in-the-air kid join them. I had to switch to a gifted class within a few months to address bullying, and it meant an extra transition.