Which equation has exactly one solution?
A.0.5(3x- 9) + 20 = 0.5(3x- 49)
B.0.5(3x- 8) = 20 (0.5x - 1)
C.0.5(3x- 9) + 20 = 5(4x- 1)
D.0.5(3x- 9) + 20 = 0.5(3x- 1)