As martha walks into the college library, she sees a friend and whispers "hi" as she passes. her whispering is likely in concordance with the "rules," or expectations, for appropriate behavior in a particular social situation. such expectations are referred to in social psychology as:
a) person perception.
b) social perception.
c) stereotype rules.
d) social norms.

   D) Social norms

Explanation:  Social norms are general social norms, meaning accepted by society as unwritten rules, and these rules relate to what behaviour is acceptable, that is, norms about how to behave. Such norms define rules, for example for certain social groups, classes, boys, girls, etc., but also at a higher cultural level, for example, some norms differ from culture to culture. In each case, social norms provide a specific model or idea of how to behave within certain groups, cultures, etc.

your answer would b. the missisipi river

hope i you : )