Let D be the domain and let ƒ be the possible function. Determine if the relation is an example of a function.

D = {x| x is a person’s social security number}
ƒ(x) = the person’s name

Yes. One output results in one input.

Yes. One input results in one output.

No. At least one input results in two outputs.

No. At least one output results in two inputs.