The data in which table represents a linear function that has a slope of zero?

a.
x y
-5 5
-4 5
-3 5
-2 5
-1 5

b.
x y
1. -5
2 -4
3 -3
4 -2
5 -1

c.
x y
-5 5
-4 4
-3 3
-2 2
-1. 1

d.
x. y
5 -5
5 -4
5 -3
5 -2
5 -1
PLEASE HELP​