In each part of this question, list clinical examination findings for each of the two underlined conditions that would help you to distinguish between them:
This comes down to basic common sense.
If the nerves are healthy, and the muscles are to blame,
This question has been repeated. Its doppelganger, Question 3.1 from the first paper of 2010, has a much better-organised college answer.
Chapter 57 (pp. 617) Neuromuscular diseases in intensive care by George Skowronski and Manoj K Saxena
UpToDate: An approach to the patient with muscle weakness
Young, G. Bryan, and Robert R. Hammond. "A stronger approach to weakness in the intensive care unit." Critical care 8.6 (2004): 416.
Dhand, Upinder K. "Clinical approach to the weak patient in the intensive care unit." Respiratory care 51.9 (2006): 1024-1041.