It's B.
If [tex]0<x<1[/tex], then it's also the case that [tex]0<x^2<1[/tex], because multiplying any number [tex]x[/tex] by a number (in this case, also [tex]x[/tex]) between 0 and 1 scales that number down.
It's not C, because [tex]2^2=4\neq3[/tex].
It's not D, because [tex]3^2=9\neq3[/tex].
