Guys, please help me!

Give an example of four different sets A, B,C and D such that (1) A ∪ B = {1, 2} and C ∩ D = {2, 3} and
(2) if B and C are interchanged and ∪ and ∩ are interchanged, then we get the same result.

The digits of a two-digit number differ by 3. If the digits are interchanged and the resulting number is added to the original number, the sum is 143. What is the original number?

In the diagram, points P, Q, R, and S are at intersections of gridlines in a 6 × 6 grid. What is the perimeter of parallelogram P QRS?
(A) 14     (B) 15     (C) 16    (D) 17    (E) 18