Hãy tìm mệnh đề sai

A. \(\forall n \in \mathbb{N},{\rm{ 2n}} \ge {\rm{n}}{\rm{.}}\)  

B. \(\forall x \in \mathbb{R},{\rm{ }}{{\rm{x}}^2} + 1 \ne x.\) 

C. \(\exists n \in \mathbb{N},{\rm{ }}{{\rm{n}}^2} = n\) 

D. \(\forall x \in \mathbb{R},{\rm{ }}{{\rm{x}}^2} > 0\)