Final answer:
Running a marathon is an example of the part of self-concept related to self-worth.
Step-by-step explanation:
Self-concept is how a person thinks about, evaluates, or perceives themselves. This includes what they believe their personal attributes to be and the value they place upon themselves. Self-esteem is how much a person values themselves. It is how much a person likes, accepts, or approves of themselves.
The part of self-concept related to self-worth refers to how individuals value themselves and their sense of self-esteem. An example of this is feeling confident and proud after accomplishing a challenging goal. In this case, the best example would be D. Running a marathon. Running a marathon requires dedication, perseverance, and physical endurance. It is often seen as an impressive achievement and can contribute positively to one's self-worth.