**Core Concept**
Kwashiorkor and Marasmus are two forms of malnutrition characterized by distinct clinical and biochemical features. Kwashiorkor is a severe form of protein malnutrition that occurs when there is an adequate calorie intake but insufficient protein.

**Why the Correct Answer is Right**
Kwashiorkor is characterized by edema, muscle wasting, and a range of systemic complications due to impaired protein synthesis and metabolism. The key pathophysiological features include:
- Edema: due to hypoalbuminemia and decreased oncotic pressure
- Hepatomegaly: due to fatty infiltration and impaired liver function
- Poor appetite and growth retardation
- Impaired immune function and increased susceptibility to infections

**Why Each Wrong Option is Incorrect**
**Option A:** Edema is a hallmark feature of Kwashiorkor, making this option incorrect.
**Option B:** Poor appetite and growth retardation are common in Kwashiorkor, so this option is also incorrect.
**Option C:** Hepatomegaly is a feature of Kwashiorkor, making this option incorrect.

**Clinical Pearl / High-Yield Fact**
To differentiate between Kwashiorkor and Marasmus, remember that Kwashiorkor patients have a relatively normal weight for height but with muscle wasting, while Marasmus patients have a reduced weight for height due to overall energy deficiency.

**Correct Answer: D.**