No they are not, 6/8 could also be represented as 3/4. Therefore they are not equivalent. You would divide each side by the factor they have in common such as 2.
A) 5×(-3)×(-4)=60
B) 1×(-7)×2=-14
C) 8×(-2)×2=-32
D) (-2)×(-4)×5=40
E) 3×4×(-7)=-84
F) 6×(-2)×(-4)=48
Increases proportionally. (C)