Which system of linear equations has infinite solutions?

A. 6x - 3y = 15
8x - 4y = 20

B. 6x - 2y = 2
X + 1/3y = 1/3

C. 3x - 3y = 15
9x - 6y = 6

D. -4x + 4y = -4
2x + 2y = 2