Is the relation a function?

Choose the answer that is entirely correct.

Responses

This relation is not a function because an output has two different inputs.
This relation is not a function because an output has two different inputs.

This relation is a function because each input has exactly one output.
This relation is a function because each input has exactly one output.

This relation is a function because all of the outputs have exactly one input.
This relation is a function because all of the outputs have exactly one input.

This relation is not a function because an input has two different outputs.