If $A=\{x:x\in R\:\:and\:\:x\geq \large\frac{1}{2}\}$ and $B=\{x:x\in R\:\:and\:\:x\geq\large\frac{3}{4}\}$ and $f:A\rightarrow B$ is defined as $f(x)=x^2-x+1$ so that $f(x)=f^{-1}(x)$ then the solution set of $x$ is ?

Question

(A) $\{1\}$

(B) $\{2\}$

(C) $\{\large\frac{1}{2}\}$

(D) No Solution