Choice b is the only one that has the first equation properly graphed. The boundary line for that equation will have intercepts that can be found by setting the opposite variable to zero.
x-intercept = 25/2 = 12.5 (on the positive x-axis)
y-intercept = 25/5 = 5 (on the positive y-axis)
That is, the boundary line has a shallow negative slope, and is shaded below. Only graph 'b' has such a line.
