The left branch is coincident with the function g (x) = (x-a) 2 at x≤0, and the right branch is at x >; 0 coincides with the function h (x) = x+(1/x)+a.

The problem is transformed into: ① the function g(x) is in x; g(0)。

To be established, it must be a ≥ 0; For ②, because x+ 1/x≥2, it should be 2+a ≥ g (0) = a 2, and the solution is-1≤a≤2.

(1), (2) At the same time, the range of change of A.

Therefore, you should choose D.