We have two functions here, and the result for g/f (x) is:
Then, we have that the domain for this function is that for which the function is defined and is real. Then, we have that the function is not defined for x = 0. Therefore, the domain is:
Or in interval notation:
In other words, the domain of the function is for any value except x = 0, that is:
Therefore, the option is the first one.