Answer: both A and B.
- A both A and B
- B either A or B
- C only A
- D only B
Correct answer: A. both A and B
Explanation: A ∩ B contains just the elements common to both sets.
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