which system of equations is consistent and dependent?
A. 2x + 3y = 6, 4x + 6y = 12
B. 5x - 2y = 7, 3x + 4y = 15
C. x + 3y = 5, 2x + 6y = 10
D. 3x - y = 4, 6x - 2y = 1