The best answer is D.
Carbohydrates get rapidly digested and are quickly converted to glucose . Once glucose levels in the blood rise, insulin that is produced by the pancreas begins to remove excess glucose from the blood and stimulates the liver to turn it into a type of starch called glycogen, which is stored in the liver and muscles.
However the body can only store a limited amount of glycogen so the excess glucose is stored as body fat (adipose tissue). This is the process of putting on weight.