If A = {2, 4, 6, 8} and B = {1, 2, 3, 4, 5}, then A - B = ______.
{1, 3, 5}
{ }
{6, 8}
{2, 4}
If A = {1,2,3,4,5,6} and B = {2,4,6,8}, then A - B = ?