Group norms are codes of conduct and standards established by groups that indicate group members in a specific environment. They can be divided into two types: descriptive norms and prescriptive norms. Descriptive norms indicate what people should do in specific situations, and it simply tells People, what behaviors are effective and appropriate. Prescriptive specifications specify what people must do in a given situation, and which of the following is approved or disapproved by people. According to the above definitions, which of the following is descriptive specifications? ['Laboratory Code.', 'Work safety standards.', 'Water conservation slogan.', 'Life planning.']