Answer: Choice A
The domain is the set {-5, -3, 1, 2, 6} which can be written as x if you want to make it clear that x is involved with the domain.
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Step-by-step explanation:
The domain is the set of x values, or the set of inputs, of a function or relation. All you have to do is list off the values in the "input" oval. Those values from top to bottom are: -3, 2, -5, 1, 6. Sort them out from smallest to largest and you get -5, -3, 1, 2, 6 which points us to choice A.
Another route you could go is eliminating choices B, C and D because -9 is not in the "input" oval.