Tonics made out of the liver are very effective in curing certain types of Anaemia because
Low levels of vitamin B12 can lead to pernicious anaemia. This type of anaemia often is treated with vitamin B12 supplements.Good food sources of vitamin B12 include:Breakfast cereals with added vitamin B12.Meats such as beef, liver, poultry, and fish,eggs and dairy products (such as milk, yogurt, and cheese),foods fortified with vitamin B12, such as soy-based beverages and vegetarian burgers.
Due to its high content of vitamin B-12, liver extract was commonly used to treat pernicious anaemia. Pernicious anaemia is low red blood cell count when your body can’t absorb vitamin B-12.Research shows scientific evidence supporting liver extracts to help increase red blood cell counts and vitamin B-12.
So,the correct option is 'D'.