The correct answer is C. Hydrogen peroxide.
Borax is a mineral that is used as a cleaning agent and a water softener. Saltpetre is a mineral that is used in gunpowder and fireworks. Sodium chloride is table salt.
Hydrogen peroxide is a chemical compound with the formula H2O2. It is a colorless liquid that is used as a disinfectant, antiseptic, and bleaching agent. It is also used in rocket fuel and in the production of other chemicals.
Hydrogen peroxide is commonly used as an antiseptic in mouthwashes and toothpastes because it is effective at killing bacteria. It is also relatively safe to use, and it does not have a strong taste or odor.
Borax, saltpetre, and sodium chloride are not commonly used as antiseptics in mouthwashes and toothpastes. Borax is a mineral that is used as a cleaning agent and a water softener. Saltpetre is a mineral that is used in gunpowder and fireworks. Sodium chloride is table salt.