$f\left(x\right)=\{\begin{array}{c}(x-a{)}^2,x\le 0\\ x+\frac{1}{x}+a,x>0\end{array}$若$f\left(0\right)$是$f\left(x\right)$的最小值，则$a$的取值范围为（   ）.

A．

[-1,2]

B．

[-1，0]

C．

[1，2]

D．

[0,2]