The answer you are looking for is option B
It is Song Dynasty (宋), and the answer is (D).
The correct answer is A. a primary group.
Primary group refers to individuals following other people's example when doing something. Here, Mary started using the language of that particular group and dressing like them. Thus, they represent her primary group in her life.
A demand schedule generally focuses on overall demand of a product or service. That is, in units or monetary value. This could be over time, yearly, quarterly, or semianually.
