Vitamin formed in the body -B 3

Vitamin formed in the body -
a) B 1
b) B 3
c) B 6
d) B 12
Correct Answer - A:B:D
Ans. is ‘b > a & d’ i.e., B3 > B1 & B12
This question is confusing one (Read text below).
Niacin (Vitamin B3) is synthesized from tryptophan inside the
body(endogenous).
Some vitamins are also formed by bacterial activity in colon :-

  1. Vitamin K
  2. Riboflavin (Vitamin B2)
  3. Vitamin B12
  4. Biotin (Vitamin B7)
  5. Thiamin (Vitamin B1)
    Thus, options a, b & d all are correct here. But the best answer
    among these is niacin as it is the only vitamin which is synthesized
    by proper anabolic metabolism