I’ll give brainliest! which relation is a function?

(1, 2), (2, 3), (3, 4), (4, 5)
(1, 2), (3, 4), (5, 6), (1, 8)
(0, 2), (0, 4), (0, 6), (0, 8)
(1, 2), (2, 1), (1, 3), (3, 1)

(1,2),(2,3),(3,4),(4,5)

Step-by-step explanation:

Inputs (x) can only be with one output (y)

answer: c

substitute in the values.

for a:

f(0) = 0 + 9

f(0) = 9

a is a solution.

for b:

f(7) = 14 + 9

f(7) = 23

b is a solution.

for c:

f (3) = 6 + 9

f(3) = 15

c is not a solution. it's supposed to be 14.

for d:

f(2) = 4 + 9

f(2)= 13

d is a solution.