3. This list describes :
-chose to close rather than integrate his restaurant in Atlanta, Georgia
-chased African American civil rights activists away from restaurant with axe hanles
-elected governor of Georgia by opponents of the 1964 Civil Rights Act

Ellis Arnell
Carl Sanders
Lester Maddox
George Busbee

Ifound the exercise on the internet. attached is the list mentioned above.in order for a compound to be considered optically active it can't have any axis or plan of symmetry. the molecule  shouldn't also  be superimposable on its mirror image.with such considerations, the compounds that are optically active are: -third compound on the first image is optically active; -second and third compound from the second image are optically actives.

It mean  additional, or one more, or sometimes one less. it's a matter of the increment, a little more or a little less, that's what the  margin  refers .