Which system of equations has NO SOLUTION?
a.
y = (5/4) x + 3

4y = 5x - 12

b.
y = 2x + 1

y = (-3/2) x + 8

c.
y = -4x - 3

y + 3 = -4x

d.
2x - 5y = 12

20x - 50y = 120