The correct answer is B. Iodine.
Iodine is a chemical element with the symbol I and atomic number 53. The element has one of the highest atomic numbers of any naturally occurring non-metal. It is a non-metallic, lustrous, deep purple-black solid at standard temperature and pressure. When finely divided, it sublimes to a deep purple vapor. Iodine dissolves in water to form a deep purple solution.
Iodine is a versatile element with many uses. It is used in the preparation of antiseptic solutions, such as iodine tincture. It is also used in the preparation of iodized salt, which is used to prevent iodine deficiency. Iodine is also used in photography, medicine, and industry.
Potassium nitrate is a chemical compound with the formula KNO3. It is a white, crystalline solid that is soluble in water. Potassium nitrate is used as a fertilizer, a food additive, and an explosive.
Iodine chloride is a chemical compound with the formula ICl. It is a white, crystalline solid that is soluble in water. Iodine chloride is used as a disinfectant, a reagent, and a precursor to other iodine compounds.
Potassium chloride is a chemical compound with the formula KCl. It is a white, crystalline solid that is soluble in water. Potassium chloride is used as a fertilizer, a food additive, and a medicine.