A researcher claims that increasing colon microbial vitamin K production can fully replace dietary vitamin K for coagulation needs in all individuals. Based on the lesson, which critique is most appropriate?

• A. This is irrelevant because vitamin K does not play a role in coagulation; therefore microbial production cannot influence clotting.
• B. This claim is correct only when people avoid all fermented foods because microbial vitamin K synthesis is inhibited by dietary microbes from fermented products.
• C. This is accurate because microbial vitamin K production in the colon is always quantitatively superior to dietary sources and fully replaces dietary requirements in every physiological state.
• D. This overstates microbial contribution: while microbes produce vitamin K, most vitamin absorption occurs in the small intestine and microbial production in the colon is supplemental and may not meet full physiological requirements for coagulation in all people.

Answer: (D)