Answer:
A) 3:5 = 12:20
Explanation:
The numbers should have the same proportion, so if you multiply the ratio with smaller numbers each by a specific number, it should equal the same ratio as the ratio with the bigger number (or even if you divide the ratio with bigger numbers to see if it equals the ratio with smaller numbers)
Example:
A) multiply 3:5 by 4:
3 x 4 = 12
5 x 4 = 20
Has the same proportion as 12:20, so that expresses a true proportion
B) multiply 14:6 by 2:
14 x 2 = 28
6 x 2 = 12
28:12 does not equal to 28:18, so not the same proportion.
C) multiply 6:2 by 7:
6 x 7 = 42
2 x 7 = 14
42:14 does not equal to 42:7, so not the same proportion.