Answer: {1, 2, 3}.
- A {1, 2, 3}
- B {2}
- C {1, 3}
- D {1, 2, 2, 3}
Correct answer: A. {1, 2, 3}
Explanation: The union collects all distinct elements: {1, 2, 3}.
A Venn diagram makes set identities visual: A∪B is everything inside either circle, A∩B is only the overlap, and the region outside both circles represents the complement of their union - directly illustrating De Morgan's law (A∪B)′ = A′∩B′.
Concept context
Types of sets, operations (union/intersection/complement), relations, and types of functions with domain and range