What is the primary source of dietary cholesterol?

The primary source of dietary cholesterol is animal products. Cholesterol is a type of lipid that is predominantly found in the cell membranes of animal cells. It's synthesized in the liver of animals and is present in significant amounts in various animal-derived foods, such as meat, dairy products, eggs, and fish.

Plant-based foods, including fruits, vegetables, whole grains, nuts, and seeds, do not contain cholesterol, as they do not have the biological machinery to produce it. Although some plant foods contain sterols that can help lower cholesterol levels in the body, they lack cholesterol itself. Therefore, animal products are the clear and primary source of dietary cholesterol, making this option the correct answer in the context of the question.