What is the symmetric difference AΔBA \Delta BAΔB of A={1,2}A = \{1, 2\}A={1,2} and B={2,3}B = \{2, 3\}B={2,3}?
{1,3}\{1, 3\}{1,3}
{1,2,3}\{1, 2, 3\}{1,2,3}
{2}\{2\}{2}
{1,2,2,3}\{1, 2, 2, 3\}{1,2,2,3}