Answer: U.
- A A
- B A'
- C U
- D Empty set
Correct answer: C. U
Explanation: A union A' = U (the universal set). Every element is either in A or its complement.
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