Answer:
The answer is C. Serum glycosylated hemoglobin (Hb A1c) .
Step-by-step explanation:
The serum glycosylated hemoglobin (Hb A1c) test is a diagnostic method used to evaluate the amount of glucose attached to the hemoglobin in blood. This technique is often applied to test the average amount of glucose attached to the hemoglobin in past three months, thus it can be applied for diabetes or pre-diabetes test. Therefore, it is the most reliable diagnostic test in this case.