HW Score: 40%, 6 of 15 points Question 6, 7.2.21 O Points: 0 of 1 Write the resulting set using the listing method. (2, 3, 9}n(1, 7} . . . . Select the correct choice below and fill in any answer boxes present in your choice. O A. {2, 3, 9}n(1, 7} = 1 (Use a comma to separate answers as needed.) O B. {2, 3, 9}{1, 7} is the empty set