A：$\forall x\notin R,$$x^2-x+\frac{1}{4}<0$

B：$\exists x\in R,$$x^2-x+\frac{1}{4}<0$

C：$\exists x\in R,x^2-x+\frac{1}{4}\ge 0$

D：$\forall x\in R,$$x^2-x+\frac{1}{4}<0$