**Core Concept**
Cold sterilization is a process that eliminates or reduces the number of viable microorganisms from a substance without the use of heat. This method is crucial in medical and laboratory settings where heat-sensitive equipment or materials must be sterilized.

**Why the Correct Answer is Right**
Cold sterilization can be achieved through the use of ethylene oxide, which is a potent bactericide and sporicidal agent. Ethylene oxide reacts with the DNA of microorganisms, ultimately leading to their death. This process is particularly useful for sterilizing heat-sensitive equipment, such as surgical instruments, medical implants, and laboratory equipment.

**Why Each Wrong Option is Incorrect**
**Option A:** Gamma radiation is not a form of cold sterilization, as it involves the use of ionizing radiation to kill microorganisms.

**Option B:** Ultraviolet (UV) light is not a reliable method for cold sterilization, as it may not penetrate deeply enough to reach all microorganisms and can be inactivated by surfaces and other materials.

**Option C:** Hydrogen peroxide vapor is a form of cold sterilization, but it is not the correct answer in this case.

**Clinical Pearl / High-Yield Fact**
One important consideration when using ethylene oxide for cold sterilization is the potential for it to react with certain materials, such as plastics and elastomers, which can lead to degradation or discoloration.

**Correct Answer: C. Hydrogen peroxide vapor.**