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: Medicine
Glycosylated haemoglobin assay is helpful in the monitoring of patients with: 
Select and explain. 
A. Addison's disease, B. Diabetes Mellitus, C. Cushing's disease, D. Graves' disease
B: Diabetes Mellitus
Answer: B: Diabetes Mellitus 
Explanation: None