Country?
I'm a big time country fan but man, I think being the legendary Britney Spear's sister you oughta stick to the same genre and live up to her reputation! I wish her the best of luck nothing less.
But this route is better for her because it was the least expected because everyone assumed that she would do pop. She clearly wants to make a name for herself and not piggy back off the success of her big sister. And not sure if you know this but Britney herself was originally going to make country-pop music (i.e. Taylor Swift) before deciding to make commercial pop music.