Correct Answer: {c}
Explanation:
A ∩ B = {a, b, c} ∩ {c, d, e, f} A ∩ B = { c } A ∩ C = { a, b, c } ∩ { c, d, e } A ∩ C = { c } ∴ (A ∩ B) ∪ (A ∩ C) = { c }.