Answer: According to the VALS system, the primary motivation guiding Marty's behavior is the SELF-EXPRESSION MOTIVATION.
Explanation: VALS known as ("Values and Lifestyles") is a proprietary research methodology used for psychological characteristics market segmentation. Developed in 1978 by social scientist Arnold Mitchell the concept is to guide companies in tailoring their products and services in order to appeal to the consumers.
It defined self-expression motivation as consumers driven by a desire for social or physical activity, variety, and risk taking.