On observation of the graphs of the two functions, we can see that f(x) has undergone some transformation to give g(x).
The original function is given as

The function is reflected over the x-axis.
The rule for the reflection over the x-axis is given as

Applying this to the function, we have the new function to be

The graph is also shifted downwards by 3 units.
This shift can be represented as

Applying this to our function, we have the new function, g(x), to be

The correct option is OPTION D.