Marginalization can be clearly defined as:

Marginalization refers to the social process through which certain groups are relegated to the fringes of society, often leading to their discredit and lack of equal access to resources, opportunities, and rights. The focus of the correct choice emphasizes the impact of disability on an individual's social standing and how society may perceive them as less valuable or worthy due to their challenges.

When individuals experience marginalization because of their disabilities, they may encounter stigma and discrimination, which can further perpetuate feelings of inadequacy and isolation. This concept is crucial for peer support specialists to understand, as they strive to empower individuals, affirm their worth, and advocate for their inclusion in all aspects of community life.

The other options do touch on aspects related to perception and belief systems but do not fully capture the essence of marginalization as a social experience that directly impacts a person's status and identity within society. They also fail to highlight the specific consequences that arise from systemic biases against those with disabilities.