Cobalt is mainly found in

Answer: Option D

Cobalt is mainly found in Vitamin B₁₂.
Cobalt is a core element of vitamin B₁₂ (cyanocobalamin), which is essential for the prevention of anemia in humans. Ruminant animals such as cows, sheep, goats, deer and camel produce vitamin B₁₂ if there is adequate Co in their diet.
Sources of Vitamin B₁₂. Vitamin B₁₂ is naturally present in foods of animal origin, including fish, meat, poultry, eggs, and dairy products.