Chemical Coordination And Integration

Diabetes mellitus is disorder of carbohydrate metabolism in which sugars in the body are not oxidised to produce energy due to lack of the pancreatic hormone insulin. The accumulation of sugar leads to its appearance in the blood (hyperglycaemia), then in the urine (glycosuria); symptoms include thirst, loss of weight, and the excessive production of urine. The use of fats as an alternative source of energy leads to disturbances of the acid-base balance, the accumulation of ketones in the bloodstream (ketosis), and eventually to diabetic coma.

So, the correct answer is (A): underproduction of insulin