In sociology, Folkways are the social norms for routines or social interactions. There is a thin line between what is right and what is being rude...
Considering the options, folkways include all of the following, except:
a. murder
Which is considered an act that is punished by law. Putting food in your mouth with a knife is being rude, but it is not punished by a law.
And shaking hands when you are introduced to someone and getting to class on time are norms for social interaction that are considered polite.
