Correct Answer: potassium nitrate

Solution : The correct option is potassium nitrate .

Potassium nitrate is also known by the name saltpetre. It is a chemical substance with a variety of uses that naturally exists as a mineral. As one of the main components of conventional gunpowder formulations, saltpetre has a long history of use in the manufacture of gunpowder. It can also be used in some fertilizers, as a food additive and for food preservation.