Answer:
D.
Step-by-step explanation:
We're working with ratios here. To get this answer, let's think of fractions. When you're simplifying, you do the same thing to the top as to the bottom. Same with ratios! To get from 12 to 2, we divide by 6. We do the same to 6. 6 divided by 6 is 1, so D is the right answer.
