**Core Concept**
Sterilizing agents are chemicals or methods used to eliminate all forms of microbial life, including bacteria, viruses, fungi, and spores, from medical instruments, equipment, and surfaces. The goal of sterilization is to create a sterile environment that prevents the transmission of infections.

**Why the Correct Answer is Right**
Sterilizing agents work by disrupting cellular functions, denaturing proteins, or damaging DNA. Examples of sterilizing agents include ethylene oxide, hydrogen peroxide gas plasma, and glutaraldehyde. These agents are effective against bacterial spores, which are highly resistant to heat and chemicals. In healthcare settings, sterilizing agents are used to prepare medical instruments and equipment for use, especially those that come into contact with patients' bodily fluids.

**Why Each Wrong Option is Incorrect**
**Option A:** Autoclaving is a method of sterilization that uses high-pressure steam, but it is not a sterilizing agent itself.
**Option B:** Disinfectants are chemicals that reduce the number of microorganisms on surfaces, but they do not eliminate all microbial life.
**Option C:** Antiseptics are chemicals that reduce the number of microorganisms on living tissues, but they do not eliminate all microbial life.

**Clinical Pearl / High-Yield Fact**
Remember that sterilization is a critical step in preventing the transmission of infections, especially in healthcare settings. Always follow proper protocols for sterilizing medical instruments and equipment to ensure patient safety.

**Correct Answer:** C. Glutaraldehyde.