A. Taking the change in y over the change in x.
We know that,
The two-point form of a line is given by,
For this form, the ordered pair are already given.
So, we have to calculate, .
That is, we need to find,
The ratio of change in y-values and x-values.
Thus, the two-point form is used to find the equation of a line by 'Taking the change in y-values over the change in x'.
Hence, option A is correct.