How many vitamins are known to be essential for human health?

The correct answer is that there are 13 vitamins known to be essential for human health. These vitamins are categorized into two groups: fat-soluble and water-soluble. The fat-soluble vitamins include A, D, E, and K, while the water-soluble vitamins encompass the B-complex group (which consists of several vitamins such as B1, B2, B3, B5, B6, B7, B9, and B12) and vitamin C.

These vitamins play critical roles in various biological processes in the body, such as energy metabolism, immune function, blood clotting, and maintaining healthy skin and vision. Deficiencies in any of these essential vitamins can lead to significant health issues, demonstrating their importance in a balanced diet.

While the other choices suggest different quantities of essential vitamins, they do not reflect the current scientific consensus regarding the number of vitamins necessary for maintaining human health. Therefore, the acknowledgment of 13 essential vitamins highlights the comprehensive understanding of human nutritional needs.