If x2 = x^2 - 2x + 2, the value of x is?

Answer: Option B

$$\sin \frac{\pi x}{2}=x^2-2x+2$$
Put value of x from options
$$\begin{array}{rl}& x=1\\ & \sin \frac{\pi }{2}\times 1=1^2-2\times 1+2\\ & \Rightarrow \sin 90^{\circ }=1-2+2\\ & \Rightarrow 1=1\end{array}$$