Answer:
The domain of the graph must be
.
Therefore,

Hence, option a is true.
Explanation:
From the graph, it is clear that the graph is heading towards positive infinity from x=-4.
The point x=-4 is included in the graph as the starting point of the graph i.e. x=4 is showing a closed circle on x=4, and heading towards positive infinity onward.
i.e. [-4, ∞)
Hence, the domain of the graph must be
.
Therefore,

Hence, option a is true.