Answer: 2.
- A 1
- B 2
- C 4
- D 0
Correct answer: B. 2
Explanation: P(∅) = {∅} has 1 element, so P(P(∅)) has 2¹ = 2 elements.
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