**Core Concept**
Muscle imbalance or misalignment of the extraocular muscles can lead to abnormal eye movements, resulting in diplopia (double vision). This condition is a common symptom of various neurological, ophthalmological, and systemic disorders.

**Why the Correct Answer is Right**
The correct answer is **Myasthenia Gravis**. Myasthenia Gravis is an autoimmune disease characterized by the production of antibodies against the acetylcholine receptor at the neuromuscular junction, leading to muscle weakness and fatigue. In the context of extraocular muscles, this results in impaired eye movements and diplopia. The pathophysiology involves the disruption of acetylcholine-mediated neurotransmission, which is essential for muscle contraction.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not directly relate to the characteristic symptom of diplopia. While various conditions can cause diplopia, Myasthenia Gravis is a more specific and common cause of this symptom.

**Option B:** This option is incorrect as it does not directly relate to the characteristic symptom of diplopia. While various conditions can cause diplopia, Myasthenia Gravis is a more specific and common cause of this symptom.

**Option C:** This option is incorrect as it does not directly relate to the characteristic symptom of diplopia. While various conditions can cause diplopia, Myasthenia Gravis is a more specific and common cause of this symptom.

**Clinical Pearl / High-Yield Fact**
Myasthenia Gravis often presents with ptosis (drooping eyelid) and diplopia, particularly after prolonged periods of activity or upon awakening. This condition highlights the importance of a thorough neurological examination and the need to consider autoimmune disorders in patients presenting with muscle weakness and fatigue.

**Correct Answer:** C. Myasthenia Gravis