This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diseases of Thyroid, Subject name: Medicine
Which of the following is associated with AV block? 
Select and explain. 
A. Hypothyroidism, B. Hypehyroidism, C. Cushing disease, D. Pheochromocytoma
A: Hypothyroidism
Answer: A: Hypothyroidism 
Explanation: Metabolic /endocrine causes of Atrioventricular Block 1. Hyperkalemia 2. Hypermagnesemia 3. Adrenal insufficiency 4. Hypothyroidism