Let M={1,2,{3,4}}M = \{1, 2, \{3, 4\}\}M={1,2,{3,4}}. Which of the following statements is mathematically true?
3∈M3 \in M3∈M
{3,4}∈M\{3, 4\} \in M{3,4}∈M
{3,4}⊆M\{3, 4\} \subseteq M{3,4}⊆M
{1}∈M\{1\} \in M{1}∈M