The correct answer is D. All of these.
Assumptions are formed based on a variety of factors, including cultural background, education, and personal experience. Cultural background can influence the way people think about the world and the assumptions they make about others. For example, people from different cultures may have different assumptions about what is considered polite or rude behavior. Education can also play a role in shaping assumptions. People who have been educated in different ways may have different assumptions about the world. For example, people who have been educated in a religious tradition may have different assumptions about the nature of reality than people who have been educated in a secular tradition. Personal experience can also influence the assumptions people make. People who have had different experiences in life may have different assumptions about the world. For example, people who have been victims of crime may have different assumptions about the safety of the world than people who have never been victims of crime.
In conclusion, assumptions are formed based on a variety of factors, including cultural background, education, and personal experience.