What Is the Universality Assumption

What is the universality assumption?

A) Language is the only important difference when comparing different cultures.
B) Cultural differences do not exist in the context of positive psychology because of the similarities of constructs across cultures.
C) Every group of people in this universe has a unique way of behaving that should be understood and appreciated.
D) What is deemed true for one group may be considered true for other groups, irrespective of cultural differences.