Determine Whether the Relation Represents a Function

Multiple Choice

Determine whether the relation represents a function. If it is a function, state the domain and range.
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A) function
Domain:{15, 20, 25, 30}
Range: { 3, 4, 5, 6}
B) function
Domain: { 3, 4, 5, 6}
Range: {15, 20, 25, 30}
C) not a function