Select the ordered pair that would be added to the table to make it not a function (2,5), (4,8), (6,12)(these are the ordered pairs) 7,14 0,2 -1,5 2,0 which one of these do i have to add to make it not a function

Arectangular lawn is 14m long and 10m wide. a strip of uniform width is mowed around the outside of the lawn. how wide is the strip when the area of the unmowed portion of the lawn is 12m². (the answer is 4m, but i need to know how to solve it)