Answer:
B
Step-by-step explanation:
Domain of a function (Graph) is the set of ALLOWED x-values. Or, the x-values for which the function is defined.
Now, looking at the graph, we can see the line is defined in the region from x = 1 till x = 4, so the domain would be 1 ≤ x ≤ 4.
Answer choice B is right.