Final answer:
A middle-aged woman in Alaska is at the highest risk for vitamin D deficiency, largely because of limited sunlight exposure in higher latitudes, which can impede the body's ability to synthesize the vitamin from sunlight.
Step-by-step explanation:
The person at most risk for vitamin D deficiency is B) a middle-aged woman living in Alaska.
Vitamin D synthesis in the body is largely dependent on sun exposure. The UV rays from the sun help the skin convert cholesterol into vitamin D, a process that is essential for the healthy development of bones through the proper absorption of calcium and phosphorus.
Factors such as living at northern latitudes with weaker sun rays, having darker skin pigmentation, which acts as a natural sunscreen, and dietary habits can all contribute to vitamin D deficiency. A middle-aged woman in Alaska is more likely to be at risk due to the higher latitude and potentially limited exposure to sunlight, especially during the long winter months. To compensate for a lack of sun exposure, vitamin D is often added to foods such as milk and orange juice, and supplements may be prescribed by a doctor.