In a park there are 15 animals: cows, cats, and kangaroos. We know that precisely 10 are not cows and precisely 8 are not cats. How many kangaroos are there in the park? (2019 Math Kangaroo Problem, Level 3-4, Question \#21) 
选项为:A:$$2$$  B:$$3$$  C:$$4$$  D:$$8$$  E:$$10$$  请回答其中一个选项.