If A={x:x is an even prime number}A = \{x : x \text{ is an even prime number}\}A={x:x is an even prime number}, what is AAA?
{2}\{2\}{2}
{2,4,6,… }\{2, 4, 6, \dots\}{2,4,6,…}
∅\emptyset∅
{1,2}\{1, 2\}{1,2}