With the same $U$, $A$, $B$, $D = A \cup B$ = ?

Question

Accepted Answer

$\{1, 2, 3, 5, 7, 9, 11, 13, 15, 17, 19\}$

Answer

$\{1, 3, 5, 7, 9, 11, 13, 15, 17, 19\}$

Answer

$\{2, 3, 5, 7, 11, 13, 17, 19\}$

Answer

$\{1, 3, 5, 7, 11, 13, 17, 19\}$

With the same UUU, AAA, BBB, D=A∪BD = A \cup BD=A∪B = ?