This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
'Dawn phenomenon' refers to: 
Select and explain. 
A. Early morning hypoglycemia, B. Non-ketotic hyperglycemia, C. Pre breakfast hyperglycemia, D. Recurrent hypoglycemia
C: Pre breakfast hyperglycemia
Answer: C: Pre breakfast hyperglycemia 
Explanation: A more common cause of pre breakfast hyperglycemia is the waning of the evening or bedtime insulin and/or the dawn phenomenon. That is, reduced tissue sensitivity to insulin between 5am and 8am (dawn), due to spikes of growth hormone released hours before, at onset of sleep. For hyperglycemia due to waning of overnight basal insulin and/or dawn phenomenon, an increase in the evening dose of the basal insulin or shifting it from dinneime to bedtime (or both) can be effective. Ref: German M.S. (2011). Chapter 17. Pancreatic Hormones and Diabetes Mellitus. In D.G. Gardner, D. Shoback (Eds), Greenspan's Basic & Clinical Endocrinology, 9e.