In the picture, we can spot two points: (6,2) and (10, -1).
First, we'll calculate the slope:

Now, using the points given we can find the point-slope equation, whose form is: y-b=m*(x-a), m is the slope and (a,b) is a point in the line.
We'll use the point (6,2), the equation will be:
y´-2 = -3/4(x-6)
Letter A