What is the commonly used dietary cutoff (in milligrams per day) to classify a mineral as a 'major' mineral rather than a 'trace' mineral?

• A. Less than 1 mg/day, because the historical definition of trace nutrients often used microgram and submilligram thresholds for public health categorization.
• B. 10 mg/day, because some older nutritional schemes placed the dividing line an order of magnitude lower to reflect typical trace element needs across diverse diets and studies comparing micronutrient requirements internationally.
• C. 1,000 mg/day, since consuming mineral supplements in gram quantities is often required to achieve optimal blood levels for most minerals that influence bone and fluid balance.
• D. 100 mg/day.

Answer: (D)