Which of the following is a valid Vitamin D daily intake according to the guideline?

• A. 200-400 IU per day
• B. 600-800 IU per day
• C. 1000-1500 IU per day
• D. 400-1000 IU per day

Answer: (D)

Vitamin D supports calcium absorption and bone health, so guidelines define a practical daily intake range to keep levels adequate. The range 400–1000 IU per day fits within what many guidelines consider safe and effective for most adults: it provides a lower amount sufficient to prevent deficiency and stays under the upper limits commonly advised. The other options either fall short for bone health needs or exceed typical daily recommendations. So, 400–1000 IU per day is the best-aligned range.