Question 20
At a birthday party, An, Bình, Châu and Dũng wear shirts of four different colours: red, yellow, black and white. An does not wear red; Bình does not wear black. Either Bình or Dũng wears white. Châu wears yellow or white, and Dũng wears black or white. What colour does An wear? Enter the original code: 0001 for black, 0002 for white, or 0003 for yellow.
