You should pick:
The relationship is linear because each y-value is 5 more than the one before it.
Here's why I think so:
If we look at the relationship between the x values and the y values, we can tell that they both increase periodically. The x values increase by 1('s), while the y values increase by 5('s).
Think about it. If y starts off at 5 when x is at 0, and then goes to 10 by x becomes 1, and increases another 5 values when x increases by 1 (again), then we are witnessing a pattern. For every 1 x value, y increases by another 5 values. Such a repetitive relationship will clearly be shown with a line. Thus, the relationship is a linear one.
Since we know that the relationship of the table is linear, and that it is linear due to the fact that the y-value continuously increase by 5's without fail, the only answer that would make sense is the second one.
Therefore, the answer is 'The relationship is linear because each y-value is 5 more than the one before it.'