Vitamins and Nutrition

Sailors' disease, also known as scurvy, is caused by a deficiency of Vitamin C. This vitamin is essential for collagen synthesis, and its lack leads to symptoms such as bleeding gums and weakness.

A raw apple (about 100 g) contains approximately 6 mg of calcium, 0.12 mg of iron, 11 mg of phosphorus, and only trace amounts of fluorine. While apples are not particularly rich in any mineral compared to other foods, among the options given, calcium is present in a higher amount than iron or fluorine. Phosphorus is also present but in a moderate amount. Therefore, calcium is the best answer among the options provided, though apples are not a rich source overall.

Vitamins A, D, and K are fat-soluble vitamins, meaning they dissolve in fats and oils. Water-soluble vitamins include the B-complex vitamins and vitamin C. Since none of the options A, B, or C are water-soluble, the correct answer is 'None'.