Seja X = {3, 4, 7, 8, 9} e Y = {1, 2, 3}, determine (X U Y).
A
(X U Y) = {3}
B
(X U Y) = {1, 2, 3, 7, 8, 9}
C
(X U Y) = {1, 2}
D
(X U Y) = {1, 2, 3, 4, 7, 8, 9}
E
(X U Y) = {7, 8, 9}