Which of the following is an example of a steroid?

Cholesterol is an example of a steroid because it belongs to a class of organic compounds characterized by a specific arrangement of four interconnected carbon rings. This structure is essential for the function of steroids in the body, as they play critical roles in various biological processes, including the formation of hormones such as testosterone and estrogen. Additionally, cholesterol serves as a precursor for the synthesis of these hormones, highlighting its importance within the steroid family.

In contrast, glucose is a simple sugar and a carbohydrate, not a steroid. Insulin is a peptide hormone and is classified as a protein, whereas vitamin C is a water-soluble vitamin known for its role as an antioxidant and in collagen synthesis. None of these substances share the unique structural characteristics that define steroids.