Which rationale best explains why vitamins are classified as micronutrients rather than macronutrients?

Vitamins are water-soluble molecules that dissolve easily in beverages and therefore are only needed in trivial trace amounts, while macronutrients are insoluble and thus required in large amounts.

Vitamins are poorly absorbed and therefore must be eaten in tiny amounts compared with macronutrients, which are fully absorbed and metabolized to provide bulk tissue components.

Vitamins are always synthesized by the gut microbiome in sufficient quantities, so dietary intake is minor unlike macronutrients that cannot be synthesized and must be consumed in bulk.

Vitamins perform catalytic or regulatory functions in small quantities and are required in milligram or microgram amounts, unlike macronutrients that provide bulk energy and are needed in gram quantities.