Final answer:
The protein that does not bind vitamin B12 and assist with absorption and transport is pepsin.
Step-by-step explanation:
The correct answer is b. pepsin.
Vitamin B12 absorption and transport involves several proteins. The intrinsic factor, which is secreted by the gastric glands, is essential for vitamin B12 absorption in the small intestine. It binds to vitamin B12 and helps it to be absorbed. Transcobalamin is a carrier protein that binds to vitamin B12 in the plasma and transports it to body cells.
R protein and transcobalamin are involved in the binding and transport of vitamin B12. Pepsin, on the other hand, is an enzyme that stimulates protein digestion and does not play a role in vitamin B12 absorption or transport.