**Core Concept**
Muscular dystrophy is a group of **genetic disorders** characterized by progressive **muscle weakness** and **degeneration**. The underlying pathology involves **dystrophin deficiency** or other **protein abnormalities** that disrupt the **muscle cell membrane** and lead to **muscle fiber damage**.

**Why the Correct Answer is Right**
The correct answer is related to the **histopathological changes** seen in muscular dystrophy, which include **variation in muscle fiber size**, indicating **regeneration and degeneration** of muscle fibers. This **heterogenicity of fiber size** is a hallmark feature of muscular dystrophy, reflecting the ongoing process of muscle damage and attempted repair.

**Why Each Wrong Option is Incorrect**
**Option A:** Inflammatory cell infiltrate is not a characteristic finding in muscular dystrophy, as it is more commonly associated with **myositis** or other **inflammatory muscle diseases**.
**Option C:** Nuclear proliferation beneath the sarcolemma is not a specific feature of muscular dystrophy, although **satellite cells** may be activated in an attempt to repair damaged muscle fibers.
**Option D:** Muscle necrosis can occur in various **myopathic conditions**, but it is not the most characteristic or specific finding in muscular dystrophy.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that muscular dystrophy is characterized by **progressive muscle weakness** and **specific histopathological features**, including **heterogenicity of fiber size**, which helps distinguish it from other **myopathic conditions**.

**Correct Answer:** B. Heterogenicity of fiber size