Final answer:
Thiamin is a water-soluble vitamin not stored in significant quantities in the body, with any excess being excreted in urine.
Step-by-step explanation:
The storage and transport of thiamin, which is vitamin B1, is explained by its water-soluble nature. Specifically, option B) It is water-soluble and readily excreted is correct. Thiamin is absorbed in the gastrointestinal tract and because it is water-soluble, it is not stored in significant quantities in the body. Instead, thiamin, along with other water-soluble vitamins, moves easily through bodily fluids and any excess is excreted in urine. Although a small amount can be stored temporarily in skeletal muscles, the liver does not primarily function as a storage site for thiamin.
However, thiamin is converted into its active form, thiamine pyrophosphate (TPP), in the liver. This coenzyme is essential for critical metabolic functions like the utilization of carbohydrates and normal brain metabolism but is not majorly stored in the liver. Therefore, it is important that thiamin is regularly included in the diet through sources such as whole grains, nuts, seeds, pulses, liver, and meat to maintain proper physiological function, as the body does not keep large reserves of this vitamin.