Answer:
The answer is B.
Step-by-step explanation:
A true proportion is a set of ratios that equal each other.
For example, 1:2=2:4 is a proportion.
As we look through the list, we observe only B equals each other. Imagine 3:4 and 9:12 as a fraction. (¾ and 9/12). If we reduce 9/12, we get ¾. Thus, 3:4 = 9:12:)
I hope this helps!