Which relations are functions?

Select Yes or No for each relation.


(2, 2), (3, 3), (4, 4), and (5, 5)------(yes,no)

(1, 2), (1, 3), (1, 4), and (1, 5)------(yes,no)

(2, 1), (3, 1), (4, 1), and (5, 1)------(yes,no)

​(2, 2), (2, 3), (5, 4), and (5, 5)------(yes,no)