Which one of the following is not a high explosive?

Explosives are generally classified into two categories: high explosives and low explosives (propellants), based on their rate of decomposition. High explosives undergo detonation, where the chemical reaction moves through the substance at supersonic speeds, creating a powerful shock wave. Examples include TNT (Trinitrotoluene), PETN (Pentaerythritol tetranitrate), and PEK (Plastic Explosive Kirkee, an RDX-based plastic explosive used by the Indian Armed Forces).

Cordite is a low explosive. It is a family of smokeless propellants developed to replace gunpowder. It is composed of nitrocellulose, nitroglycerin, and petroleum jelly. Unlike high explosives, cordite undergoes deflagration (rapid subsonic burning). It is designed to burn steadily to produce gas pressure that propels a bullet or shell out of a gun barrel, making it a propellant rather than a high explosive.