which expression is equivalent to (c-2d) times (3c-2d)?
A: c(c-2d)+3c(c-2d)
B: c(3c-2d) - 2d(3c-2d)
C: 3c(c-2d) + 2d(c-2d)
D: 3c(c-2d) - 3c(3c-2d)
