सामाजिक समूह को 'सामाजिक अंतःक्रिया की एक प्रणाली' के रूप में किसने परिभाषित किया है?

Which of the following is considered the primary and basic social group in society?

A researcher is comparing the influence of family and student councils on learners' values. Which distinction between social groups is most relevant for understanding the nature of these influences?