Explanation:

The abbreviation RDX stands for Research Department Explosive or Royal Demolition Explosive. It is an odorless, tasteless white organic compound that acts up as an explosive. 

• It is an exploding compound related to nitramines, a type of explosion derived from organic nitrate. It is also known as hexogen, cyclonite, and T4 RDX. Its molecular name and formula are Cyclotrimethylenetrinitramine and C3H6N6O6, correspondingly.

• RDX is a white, rigid crystalline solid that is insoluble in water and very slightly soluble in a few other solvents. Because it is sensitive to pounding, its primary nonmilitary application is in blasting caps. It is frequently combined with other medicines to reduce its sensitivity.

• Georg Friedrich Henning from Germany created and patented RDX in 1898. However, it was not employed until the Second World War, when most combatant states initially adopted this RDX. A secret procedure evolved in the United States in the creation and adoption of this RDX. Canada and the United States developed RDX on a big scale in a relatively secure and cost-effective manner.

Hence option 4th is correct.