Answer: Option (b) is incorrect option
Explanation:
Informal laws are the regulations that are unspoken behavior norms which people can get obligated for following as per their liking.This is a casual behavior which is connected with law for following unlike formal norms that are written laws of legislation for obeying.
Other options are incorrect because informal norms are not considered as legislated by the government system, are not written rules and regulation or followed as persistently as law by people.Thus, the correct option is option(b).