The difference between Marasmus and Kwashiorkor is that 

Marasmus is a simultaneous deficiency of proteins and calories, while kwashiorkor is due to just protein deficiency
unaccompanied by calorie deficiency. Both marasmus and kwashiorkor are forms of protein-energy malnutrition (PEM), but they differ in their underlying causes and manifestations. Marasmus is primarily caused by a deficiency of both proteins and calories. It occurs when there is a prolonged inadequate intake of overall food, resulting in severe malnutrition. Marasmus is characterised by severe wasting, muscle and fat loss, stunted growth, thin limbs and a weakened immune system. Kwashiorkor is primarily caused by a deficiency of protein without a concurrent deficiency of calories. It often occurs when there is a sudden transition from a protein rich diet (such as breastfeeding) to a diet
low in protein but high in carbohydrates. Kwashiorkor is characterised by edema (swelling) in the extremities and face, skin changes, hair loss, lethargy and impaired growth and development. 

(1) Neither marasmus nor kwashiorkor is caused by the deficiency of vitamin B or vitamin D. Deficiency of vitamin
D causes rickets (in children) and osteomalacia (in adults).

(2) Both marasmus and kwashiorkor involve deficiency of proteins and calories.

(4) Marasmus is a deficiency of proteins and calories. Kwashiorkor is due to a deficiency of proteins.