The correct answer is A. Glucose levels.
Explanation
Insulin is a hormone in the human body that has the function of regulating metabolism. Insulin is produced by the pancreas. Mainly insulin is necessary for the body to neutralize the coordinated action of other hormones, which generate hyperglycemia (high levels of sugar in the blood), that is, insulin keeps blood glucose levels in an ideal level by avoiding glucose to be too high or too low. So, the correct answer is A. Glucose levels.