Intestinal bacteria are main source of which one of the following vita

Intestinal bacteria are main source of which one of the following vitamins ?

Vitamin E
Vitamin C
Vitamin B₁₂
Vitamin A
This question was previously asked in
UPSC NDA-2 – 2021
The correct answer is C) Vitamin B₁₂.
Bacteria residing in the large intestine (colon) of humans are known to synthesize several vitamins, including Vitamin K and various B vitamins, particularly Vitamin B₁₂ (cobalamin).
While intestinal bacteria produce B₁₂, its absorption primarily occurs in the ileum (part of the small intestine) and requires intrinsic factor produced by the stomach. Dietary intake is the main source of Vitamin B₁₂ for humans, as the bacterial production in the colon might not be sufficient or readily absorbable. However, among the options provided, B₁₂ is the vitamin most notably associated with production by intestinal bacteria.