The parent function is given by
and the transformation function is given by
We can see that, 6 has been added to the function f(x) to get the function g(x).
We know that when we add some constant 'c' in the function then the function gets shifted upward by 'c' units.
Therefore, we will get g(x), when we will shift f(x) upward by 6 units.
Both functions are linear function hence, the asymptote of g(x) is the asymptote of f(x) shifted six units up.
D is the correct option.