The correct answer is option 'C' - Cellulose.

Explanation:

Vegetarian diets are typically high in carbohydrates, as they mainly rely on plant-based foods for energy. Carbohydrates are one of the three macronutrients, along with protein and fat, that make up a balanced diet. They provide the body with energy and fiber, which is essential for maintaining a healthy digestive system.

Among the different types of carbohydrates, cellulose is the most abundant in the diet of strict vegetarians. Here are some reasons why:

- Cellulose is a complex carbohydrate that is found in the cell walls of plants. It is the main component of plant fibers, making up about 40-50% of the dry weight of most plants.
- Vegetarians consume a lot of fruits, vegetables, and whole grains, all of which are rich in cellulose. These foods are also high in other types of fiber, such as pectin and lignin, which contribute to the overall fiber content of the diet.
- Cellulose is not digestible by humans, but it plays an important role in promoting digestive health. As it passes through the digestive tract, it adds bulk to the stool and helps to regulate bowel movements. It also binds to cholesterol and other toxins, helping to remove them from the body.
- Other types of carbohydrates, such as simple sugars like lactose and maltose, are less abundant in the diet of strict vegetarians. Lactose is mainly found in dairy products, which are typically not consumed by strict vegetarians. Maltose is a disaccharide that is formed when starch is broken down, but it is not a major component of most plant-based foods.

In summary, cellulose is the most abundant carbohydrate in the diet of strict vegetarians due to its presence in plant-based foods and its role in promoting digestive health.