**Core Concept**
The body primarily stores carbohydrates in the form of glycogen, a complex polysaccharide that serves as a readily mobilizable energy reserve. Glycogen is synthesized and broken down in the liver and muscles, playing a crucial role in maintaining blood glucose levels and providing energy for various cellular processes.

**Why the Correct Answer is Right**
Glycogen is the primary carbohydrate storage molecule in the body due to its high energy density and rapid mobilization. It is synthesized from glucose molecules through the action of the enzyme glycogen synthase in the liver and muscles. Glycogen is then broken down into glucose-1-phosphate by the enzyme glycogen phosphorylase, which is then converted into glucose-6-phosphate and eventually released into the bloodstream. This process is essential for maintaining blood glucose levels, especially during fasting periods.

**Why Each Wrong Option is Incorrect**
**Option A:** Glycogen is not stored in the form of starch, which is a complex carbohydrate found in plants. Starch is broken down into glucose during digestion, but it is not stored in the body as a reserve.

**Option B:** Lactate is not a major carbohydrate storage molecule. While lactate can be used as an energy source by muscles, it is not stored in significant quantities in the body.

**Option C:** Glucose is not stored in the body as a reserve, but rather is constantly being synthesized from amino acids, lactate, and glycerol through gluconeogenesis. Glucose is also obtained from the diet.

**Clinical Pearl / High-Yield Fact**
Glycogen depletion can occur in individuals with glycogen storage diseases, such as glycogen storage disease type I (GSD I), where the enzyme glucose-6-phosphatase is deficient, leading to hypoglycemia and other metabolic disturbances.

**Correct Answer: C. Glycogen**