Answer
The given relation is a function because every person who lives in Cincinnati, Ohio is assigned witih only one specific day of the year for his/her birth date.
Work Step by Step
Every resident of Cincinnati, Ohio is born on a specific day of the year.
Some residents may share the same specific day of the year for their birth date, but no person was born on two different days of the year.
This means that each element of the first set (resident of Cincinnati, Ohio) is assigned only one specific day of the year as his or her birth date.
Thus, the given relation represents a function.
