Answer:
B) Δy
Explanation:
Where we analyse a linear function, we must consider variations of each variable.
Also, linear functions variate according to its constant ratio of change, which is defined as
![r=(\Delta y)/(\Delta x)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/c9ytwnjyuru7sb2k5kia67oyjdqfnclioo.png)
Which is the variation of the vertical value, regarding x-values.
So, if we want to show this variation, we must include a colum
, which shows the variation we need, because it's the dependent value, then we can analyse the variation of the function for a certain x-interval.
Therefore, the right answer is B.