Fructose is often regarded as the sweetest sugar among the options provided. It is a natural sugar found in fruits, honey, and some vegetables. Fructose is sweeter than glucose, sucrose (which is a combination of glucose and fructose), and maltose. Due to its high sweetness level, fructose is commonly used as a sweetener in various food products and beverages.

(D) Kwashiorkor

Kwashiorkor is a disease caused by the deficiency of protein in the diet. It is a form of malnutrition that particularly affects children in regions where there is a lack of access to an adequate protein source. Symptoms of kwashiorkor include edema (swelling), stunted growth, and changes in skin and hair. The other options listed—Hypokalemia, Dermatosis, and Goitre—are not specifically caused by a deficiency of protein. Hypokalemia is a low potassium level, dermatosis refers to various skin disorders, and goitre is often associated with iodine deficiency leading to thyroid gland enlargement.