Answer:
"all real numbers"
Explanation:
The domain is the set of x-values for which the function is defined.
Domain is also the input of the function (graph).
The graph shown has arrows in both directions. It means that the graph goes on in both directions. If we were to think correctly, we would say the graph would go on-and-on in both +ve x and -ve x directions. So there would be values of x for all real numbers (going to infinity and negative infinity)
Hence, the domain is all real number, the last answer choice is right.