Rational behavior requires thinking at the margin. which example represents this type of thinking?

The examples are:
-deciding whether a second burger is worth the extra $2 
-deciding whether the overtime pay is worth working on your day off
-deciding whether to pay a fine for polluting the local harbor or installing antipollution machinery

In rational behavior, our decision-making process is always based on which decision give the maximum/optimal benefit for use, after deducting all possibilities with a logical approach.
All the actions above represents this very concept of rational behavior.

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.