Answer:
A. -2 <= x <= 4
Explanation:
Since its a line (continuous) graph, the answer cannot be B. It cannot be C because all the points are filled-in circles instead of open circles.
The answer would be A because when you go right to left on a line graph, you include ALL the values that lie between the graph (including real numbers that lie on the lines).
Therefore, the domain of this function would be -2 <= x <= 4 (the 1st option).
I hope this helps! :D