Answer:
D
Step-by-step explanation:
Since we are being asked to find the domain, we are only interested in the values of x, hence we can discard the options which give y-values (we can ignore option B)
If we plot the function, and observe the graph (see attached), we can clearly see that the x-values can be positive or negative.
Hence A is wrong because it doesn't take into account the negative x- values.
Similarly, C is wrong because it doesn't take into account the positive x-values.
We are left with only option D.
We can verify this by once again looking at the graph and seeing that x can be any negative value, zero or any positive value (ie x can be all real numbers). Hence D is the answer.
