Which of the following carbohydrates is known as roughage?

The term "roughage" refers to the indigestible parts of plant foods, primarily dietary fibers, that provide bulk and aid in digestion. Fiber is a crucial component of the diet that helps regulate the body's use of sugars and supports overall digestive health. It can be classified into soluble fiber, which dissolves in water, and insoluble fiber, which does not dissolve in water and is the component most commonly referred to as roughage. This category of carbohydrates includes substances such as cellulose, which is a type of insoluble fiber that helps to add bulk to stool and promote regular bowel movements.

In the context of the other options, sugars and starches are types of carbohydrates that are digestible and provide energy, but they do not contribute to the roughage or fiber aspect of diet. Cellulose is indeed a type of dietary fiber, but the term "roughage" more broadly encompasses all types of dietary fibers, making fibers the most accurate and encompassing answer in this situation.