Biomolecules

Step 1: Recall the chemical names of B-complex vitamins.
- Vitamin B : Thiamine - Vitamin B : Riboflavin - Vitamin B : Niacin (or Nicotinic acid / Nicotinamide) - Vitamin B : Pantothenic acid - Vitamin B : Pyridoxine (also pyridoxal, pyridoxamine) - Vitamin B : Biotin (sometimes called Vitamin H) - Vitamin B : Folic acid (or Folate) - Vitamin B : Cyanocobalamin (a common synthetic form), or more generally, cobalamin.
It contains cobalt.

Step 2: Identify the vitamin corresponding to cyanocobalamin.
Cyanocobalamin is Vitamin B .
This matches option (3).