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}