If the system of equations represented by ax + by = c and px + qy = t has no solution, what must be true of these equations?

a. a ≠ p, b ≠ q, c ≠ t
b. a = p, b = q, c ≠ t
c. a = p, b = q, c = t
d. a ≠ p, b ≠ q, c = t