According to Your Textbook,why Was Muzafer Sherif's Research Crucial for the Development

According to your textbook,why was Muzafer Sherif's research crucial for the development of social psychology?

A) because it introduced the idea of cognitive dissonance
B) because it marked the beginning of the pluralistic approach that continues to characterize the field
C) because it firmly established the importance of an interactionist perspective
D) because it demonstrated the feasibility of studying complex social issues in a rigorous,scientific manner