Final answer:
The self-management skill that helps to build the belief in one's capability to make healthy lifestyle changes is Self-Confidence (C), closely related to self-efficacy, which is critical for initiating health-related behaviors.
Step-by-step explanation:
The self-management skill that helps build the feeling that one is capable of making healthy changes in a lifestyle is Self-Confidence (C). Self-confidence refers to your level of confidence in your own abilities and is closely associated with the concept of self-efficacy.
Self-efficacy is the belief that one has the power to execute the behaviors necessary to produce specific performance attainments. This belief can impact how one feels, thinks, motivates oneself, and behaves. A positive attitude and a goal-setting mindset are important, but self-confidence directly nurtures the belief in one's own capabilities, which is essential for taking proactive steps towards a healthier lifestyle.
To further break down these terms, self-efficacy is part of one's self-concept, which encompasses all of our thoughts and feelings about ourselves. It contrasts with an external locus of control, where individuals believe that their outcomes are outside of their control.
Conversely, an internal locus of control, a component of self-regulation often compared to will power, is the belief that we are in control of our own outcomes, which is intrinsic to self-efficacy. In the context of Erikson's theory of psychosocial development, feeling competent is seen as a crucial task during adolescence, which aligns with the development of self-confidence and empowerment to make positive lifestyle changes.