Question

A = {∅,{∅},2,{2,∅},3}, which of the following is true?

(a) {{∅,{∅}} ∈ A

(b) {2} ∈ A

(c) ∅ ⊂ A

(d) 3 ⊂ A

The question was posed to me in unit test.

This is a very interesting question from Types of Set in chapter Basic Structures: Sets, Functions, Sequences, Sums and Matrices of Discrete Mathematics

Answer 1

Correct option is (c) ∅ ⊂ A

Explanation: Empty set is a subset of every set.