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: Surgery
Which is not a test for diabetes mellitus aEUR' 
Select and explain. 
A. Fasting blood sampling, B. Random blood sampling, C. D-xylose, D. Oral glucose tolerance test
C: D-xylose
Answer: C: D-xylose 
Explanation: D-xylose Diagnostic criteria for diabetes 1) Symptoms of diabeties plus random blood glucose concentration > 200 nzg/d1. (Random is defined as without regard to time since last meal) or 2) Fasting plasma glucoseQ > (126 mg/di) (Fasting is defined as no caloric intake for at least 8 hrs) or 3) Two hour plasma glucoseQ > (200mg/dl) during an oral Gil In the absence of unequivocal hyperglycemia and acute metabolic decompensation these criteria should be confirmed by repeat testing on a different day. Diagnostic criteria for evaluation of standard Glucose Tolerance test according to Diabetes expe committee Normal Glucose tolerance Impaired Glucose tolerance Diabetes mellitus Fasting plasma glucose (mg/dl) < 100 100 -- 125 >126 Two hours after glucose ingestion (75g) < 140 >140 but < 200 > 200