Final answer:
Fat-soluble vitamins are absorbed at the brush border of the enterocytes by incorporating into micelles and then packaged into chylomicrons for transport.
Step-by-step explanation:
The student has asked about the process of vitamin absorption, specifically how fat-soluble vitamins are absorbed in the body. During the absorption of dietary fats, bile salts and lecithin emulsify these fats into micelles. These micelles then transport the fat-soluble vitamins to the brush border of the enterocytes in the small intestine. Once at the enterocytes, the fat-soluble vitamins are absorbed into the cells and repackaged into chylomicrons. The chylomicrons, a type of lipoprotein, then move into the lacteals of the villi to enter the lymphatic system and eventually the systemic circulation.
Therefore, the correct answer to the question "During vitamin absorption, water-soluble vitamins are absorbed into the bloodstream, whereas fat-soluble vitamins are carried to the brush border for absorption by?" is a. Chylomicrons.