Chapter 2 - Set Theory - 2.4 Set Operations and Venn Diagrams with Three Sets - Exercise Set 2.4 - Page 94: 103

$VI$

"It's Now or Never" was recorded by Elvis Presley, a solo artist. It sold 20 million copies and was released in 1960. Thus, this song belongs to the sets "Recorded before 1990" and "Sales exceeded 15 million", but not to "Recorded by a group." Therefore, it must be written in Region $VI$.