Which of the following foods is a source of saturated fats?

Butter is a well-known source of saturated fats. Saturated fats are typically solid at room temperature and are primarily found in animal products. Butter is made from cream, which contains high amounts of saturated fat, contributing to its rich texture and flavor.

In contrast, olive oil, which is derived from olives, is high in unsaturated fats, particularly monounsaturated fats, which are considered healthier for heart health. Fish tends to have a higher content of omega-3 fatty acids, which are a type of polyunsaturated fat and beneficial for cardiovascular health. Fruits generally contain very low levels of fats, and when they do have fat, it is predominantly unsaturated.

Thus, butter stands out as a clear source of saturated fats, making it the correct answer in this context.