What is the acronym of hotel DND code?​

Do not disturb

Explanation:
A hotel guest might have a sign hanging on the outside of their door that says DND. In general, avoid knocking on this guest’s door until they remove the sign.

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.