Given that A = {1, 5, 7} B = {3, 9, 12, 15} C = {2, 4, 6, 8} Find (A ∪ B) ∪ C

A.

{1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 15}

B.

{1, 2, 3, 5, 6, 8, 12, 15}

C.

{2, 4, 5, 9, 12, 15}

D.

{1, 5, 6, 7, 8, 9, 12, 15}

Correct answer is A

{A ∪ B ∪ C}

{A ∪ B} = {1, 3, 5, 7, 9, 12, 15}

∪ C={2,4,6,8}

{A ∪ B} ∪ C = {1, 3, 5, 7, 9, 12, 15} ∪ {2, 4, 6, 8}

= {1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 15}

{A ∪ B} ∪ C = {1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 15}