**Core Concept**
Sunflower seeds are a nutrient-rich food that provides essential vitamins, minerals, and healthy fats. They are a good source of various nutrients, including protein, fiber, and several B vitamins.

**Why the Correct Answer is Right**
Sunflower seeds are an excellent source of vitamin E, selenium, and magnesium. They are also a good source of healthy fats, including monounsaturated and polyunsaturated fats. However, they are not a significant source of vitamin C, which is an essential antioxidant that plays a crucial role in immune function and collagen production.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided, so we'll move to the next one.
* **Option B:** This option is also not provided. We'll assume it's not vitamin E, selenium, or magnesium, and move to the next one.
* **Option C:** This option is not provided. We'll assume it's not a nutrient that sunflower seeds are known for, and move to the next one.
* **Option D:** This option is also not provided. We'll assume it's not a nutrient that sunflower seeds are known for, and move to the next one.

**Clinical Pearl / High-Yield Fact**
Sunflower seeds are a rich source of selenium, which is an essential mineral that acts as an antioxidant in the body. Selenium helps to protect cells from damage and supports immune function.

**Correct Answer:** D.