This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Myasthenia Gravis and Muscular dystrophy, Subject name: Medicine
Ice pack test is done for? 
Select and explain. 
A. Myasthenia Gravis, B. Multiple system atrophy, C. Hyperparathyroidism, D. Hypokalemic periodic paralysis
A: Myasthenia Gravis
Answer: A: Myasthenia Gravis 
Explanation: Ice pack test: In patients suspected of palpebral ptosis and/or ophthalmoparesis due to myasthenia gravis. Investigations for the remaining choices mentioned in the question Disease Features Multiple system atrophy MRI showing hot cross buns sign and putaminal atrophy Hyperparathyroidism PTH assay and Technetium Peechnetate Scan. Hypokalemic periodic paralysis C.M.A.P compound muscle action potential shows low amplitude and shows no improvement in exercise.