उत्तर : 2. "Dry Ice"
व्याख्या :

Answer: B) Dry Ice Explanation: Dry ice or Cardice is the solid form of Carbon dioxide.   1. It has an advantage of lower temperature than the water ice and doesn't leave any residue.   2. The reason why it is called as Dry ice is because unlike the normal ice, it won't melt into liquid form. It directly evaporates into the air as gas. That is Solid to gas form passing through liquid state is a phenomenon called as Sublimation.   3. The primary use of dry ice is as cooling agent.