The correct answer is option 2: Vitamin B12 deficiency causes the disease Pernicious anemia. Pernicious anemia is a condition where the body is unable to absorb enough vitamin B12 from the diet. This usually occurs due to a lack of a protein called intrinsic factor, which is needed for the absorption of vitamin B12 in the intestines. Without enough vitamin B12, the body is unable to produce enough healthy red blood cells, leading to the development of anemia. Symptoms of pernicious anemia can include fatigue, weakness, shortness of breath, pale skin, and neurological problems. It is important to treat pernicious anemia by addressing the underlying vitamin B12 deficiency, either through dietary changes or supplements. Alert - The correct answer should be option 2: Vitamin B12.