## Core Concept
The question assesses the understanding of **impairment, disability, and handicap** as defined in the World Health Organization's International Classification of Impairments, Disabilities, and Handicaps (ICIDH). Impairment refers to any loss or abnormality of psychological, physiological, or anatomical structure or function. Disability is a restriction or inability (resulting from an impairment) to perform an action in the manner or within the range considered normal for a human being. Handicap is a disadvantage for a given individual, resulting from an impairment or a disability, that limits or prevents the fulfillment of a role that is normal (depending on age, sex, social, and cultural factors) for that individual.

## Why the Correct Answer is Right
The scenario describes a person who has lost a leg (an **impairment**) and as a result, is unable to walk (a **disability**). The correct answer focuses on the inability to walk, which is a functional limitation or restriction. This aligns with the definition of **disability**, which is a restriction or inability to perform an action in the manner or within the range considered normal for a human being due to an impairment.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is not provided, but typically, impairment would refer to the loss of the leg itself.
- **Option B:** Similarly, this option is not provided, but it might relate to handicap, which is about societal disadvantage.
- **Option C:** Without the specific text, we can't directly address it, but if it refers to impairment, it would be incorrect because the question emphasizes the functional limitation (inability to walk), not the loss of the leg.
- **Option D:** Assuming this is not the correct answer, if it refers to handicap, it would be incorrect in this context because the focus is on the functional limitation (disability) rather than the disadvantage in society.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the terms **impairment, disability, and handicap** are often used interchangeably but have distinct meanings in medical and rehabilitative contexts. Understanding these concepts is crucial for providing appropriate care and support to patients with various conditions.

## Correct Answer Line
**Correct Answer: C. Disability**