If you continue operating the tractor at its current level, how many acres can you expect to fertilize in the next hour?
A.5.96 acres
B. 11.92 acres
C. 12.92 acres
D. 19.87 acres

The relation you have shown is not a function.

In order to be a function, a relation's domain must be continuous in that no x-value is not repeated in any of the points. Since the first two points of the relation are (5,1) and (5,3), you can see that they have the same x-value, meaning that this is not a function.

One quick way you could test this is to quickly sketch a graph and use the vertical line test to see if the relation in question is a function. If it cross the vertical line once in all places, it is a function - if it crosses the vertical line more than once in any place, it is not a function.