A Physician Has Explained to a Patient That He Has

A physician has explained to a patient that he has developed diabetic neuropathy in his right foot. Later that day, the patient asks the nurse what causes diabetic neuropathy. What would be the nurses best response?

A) Research has shown that diabetic neuropathy is caused by fluctuations in blood sugar that have gone on for years.
B) The cause is not known for sure but it is thought to have something to do with ketoacidosis.
C) The cause is not known for sure but it is thought to involve elevated blood glucose levels over a period of years.
D) Research has shown that diabetic neuropathy is caused by a combination of elevated glucose levels and elevated ketone levels.