Determine Whether the Graph Illustrated Represents a Function $\mathcal { R }$

Multiple Choice

Determine whether the graph illustrated represents a function. Give the domain and range of the relation or function.
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A) not a function domain: {x | x ? 3} range: $\mathcal { R }$
B) not a function domain: $\mathcal { R }$ range: {y | y ? 3}
C) function domain: {x | x ? 3} range: $\mathcal { R }$
D) function domain: $\mathcal { R }$ range: {y | y ? 3}