The relation between variable is linear if equal increase in one variable results in constant change in variable y.
In option 1, it can be observed that as value of x increases by 1 unit then value of y increases by 2 unit.
For the other options, it can be observed that as value of x increase then increase in value of y is not constant. So option 1 represents the linear function.
Answer:
x y
0 3
1 5
2 7
3 9
