Percentages
We know there are 50 dogs and 30 cats at the shelter. This gives us a total of 80 animals.
We also know 12 dogs and 8 cats have spots. This means a total of 20 animals have spots.
There are 20 animals with spots out of 80 animals, this gives us a percentage of:

Operating: 2000/80 = 25%
Answer: D. 25%