Question

If φ is a null set, then which one of the following is correct? 

(a) φ = 0 

(b) φ = { 0 }

(c) φ = { φ } 

(d) φ = { }

Answer 1

Correct option is (d) 

Explanation :

If φ is a null set, then its other representation is { }. 

i.e., φ = { }.