Which of the following has the same set of solutions?

Select one:

a.
y - 8x = -20; 2x + 4y = 10


b.
3y - 5x = -12; 3x - 3y = 12


c.
y + x = 1; - x - y = 1


d.
y - 5x = -4; 20x - 4y = 16