P = {3, 9, 11, 13} and Q = {3, 7, 9, 15} are subset of the universal set ξ = {1, 3, 7, 9, 11, 13, 15} find P^I ∩ Q^I

• A.{3, 9}
• B.{5, 7, 9}
• C.{1}
• D.{1, 11}