The union of sets P = {1, 2, 3, 4, 5, 6} Q = {4, 5, 6, 7, 8, 9} is given by which of the following?



{1, 2, 3, 4, 5, 6, 7, 8, 9}

{1, 2, 3, 4, 4, 5, 5, 6, 6, 7, 8, 9}

ø

{4, 5, 6}