Answer:
C
Step-by-step explanation:
to be a linear function the change in X and the change in Y has to be the same hence slope
A. x changes by+ 1 see 2,3,4,5, and y changes by +5, +7, +9 so A is not a linear function
B. X changes by -1 in all, y changes +1 for first 3 then -1 last, so B is not a linear function
C. X changes by +1 for all and y changes by -6 for all so is it is a linear function
D x changes by +1 for all and y changes by -1, +1, +3 so no linear fn.