Rewrite each ratio as a fraction and reduce. If the reduced fractions are euqal, it is a proportion.
A. 20/5 = 4; 4/2 = 2; not a proportion
B. 3/4 = 3/4; 12/16 = 3/4; proportion
C. 18/8 = 9/4; 3/2 = 3/2; not a proportion
D. 12/24 = 1/2; 3/4 = 3/4; not a proportion
E. 6/9 = 2/3; 3/2 = 3/2; not a proportion
F. 8/6 = 4/3; 4/3 = 4/3; proportion