1. **Problem:** Identify the correct statement about myasthenia gravis. 2. **Explanation:** Myasthenia gravis is an autoimmune disorder affecting the neuromuscular junction, leading to muscle weakness. 3. **Options:** - (A) Central inhibition disorder of neuromuscular synthesis causing defects. - (B) It is an autoimmune disease. - (C) Earliest affected during training. - (D) Deep tendon reflexes are reduced. 4. **Analysis:** - (A) Incorrect: Myasthenia gravis is a peripheral neuromuscular junction disorder, not central. - (B) Correct: It is a common autoimmune disease. - (C) Incorrect: Muscle weakness worsens with activity but training is not the earliest affected. - (D) Incorrect: Deep tendon reflexes are usually normal. 5. **Final answer:** (B) It is an autoimmune disease.