Final answer:
Jason's career choice in professional mixed martial arts can best be explained by Reaction formation, a defensive mechanism where he might be expressing the opposite behavior of his anxiety-producing experiences of abuse.
Step-by-step explanation:
The concept that best explains Jason's choice of a career in professional mixed martial arts is most likely C) Reaction formation. This concept suggests that because Jason was physically abused and neglected by his mother, he could be unconsciously expressing aggression in a socially acceptable or controlled environment such as mixed martial arts as a way to cope with his past. The aggression he learned through observational learning from his abusive mother might be redirected in the sports arena instead of in antisocial behavior.
Although genetics and socioeconomic factors may also play a role, the context provided leans more towards psychological coping mechanisms developed in response to his early social environment. Sam's influence on him may have had an impact, but there is not enough information to determine that. Reaction formation is a defense mechanism that involves expressing the opposite behavior of one's unacceptable or anxiety-producing impulses, which corresponds with the concept of handling abuse through an outlet like martial arts.