Why are carbohydrates not considered essential?

1. Protein can be converted for this purpose
2. Protein Fats be converted for this purpose
3. Vitamin D be converted for this purpose
4. None of these

Through gluconeogenesis, the liver converts amino acids (protein) and glycerol (fats) into glucose when carb intake is low that is why carbohydrates are not considered essential. The brain requires 120g glucose/day, but ketones can substitute during starvation. Essential nutrients (like vitamins) cannot be synthesized internally.