Answer: {(1,a),(1,b),(2,c)}.
- A {(1,a),(2,b),(3,c)}
- B {(1,a),(2,a),(3,a)}
- C {(1,a),(1,b),(2,c)}
- D {(1,c),(2,b),(3,a)}
Correct answer: C. {(1,a),(1,b),(2,c)}
Explanation: A function requires each input to have exactly ONE output. Here 1 maps to both a and b, so it is not a function.
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