Answer: B positive numbers can be the universal set of the set of even numbers and set of prime numbers.
Explanation:
Given: Carrie is finding the set of even numbers within the set of prime numbers. She starts by considering only positive numbers.
Set of even positive numbers = {0,2,4,6,8,10.............}
Set of prime numbers={2,3,5,7,11,..............}
Universal set is the collection of given sets and itself in a certain context.
So the universal set for the given sets can be positive numbers ={0,1,2,3,4,......................} which contains all the even positive number and all the prime number.
All real numbers can be universal set but in the given sets we talk only about positive numbers ,so there is no need for this.
Prime numbers cannot be the universal set of the given sets as it does not contains all the even numbers .
Even numbers cannot be universal set of the given sets as it doesn't contain all the prime numbers.