Answer:
(c) (-∞, -2] ∪ (-1, ∞)
Explanation:
You want the range of the piecewise function shown in the graph.
Range
The range is the vertical extent of the graph, the set of possible output values of the function.
This graph shows a gap between y = -2 and y = -1. The value y = -2 is included in the range, but the value y = -1 is not. (That's what the open circle means.)
Hence, the range is ...
(-∞, -2] ∪ (-1, ∞)