Which of the following conditions is responsible for the presence of sugar in the blood of diabetic patients?

The correct answer is "Low production of insulin". Insulin is a hormone produced by the pancreas that regulates the amount of sugar (glucose) in the blood. In diabetic patients, the pancreas either produces very little insulin or no insulin at all, which results in high levels of glucose in the blood. This happens because insulin is responsible for helping glucose enter the body's cells to be used as energy. When there is not enough insulin, glucose remains in the bloodstream, leading to high blood sugar levels. Therefore, low production of insulin is responsible for the presence of sugar in the blood of diabetic patients.