**Core Concept**
Autoclaving is a widely used method for sterilization in medical and laboratory settings. It involves using high-pressure steam to kill microorganisms and achieve complete sterilization. The conditions required for autoclaving are crucial to ensure the effectiveness of the process.

**Why the Correct Answer is Right**
The correct conditions for autoclaving include a temperature of 121°C, a pressure of 15 psi (pounds per square inch), and a holding time of 15-20 minutes. This allows the steam to penetrate the materials being sterilized and achieve the desired level of sterilization. The high temperature and pressure denature proteins, disrupt cell membranes, and ultimately kill microorganisms, including bacterial spores.

**Why Each Wrong Option is Incorrect**
**Option A:** Temperature of 80°C - This temperature is not sufficient to achieve complete sterilization, as it may not effectively kill bacterial spores.

**Option B:** Pressure of 5 psi - This pressure is too low to ensure effective sterilization, as it may not be sufficient to penetrate the materials being sterilized.

**Option C:** Holding time of 5 minutes - This holding time is too short to ensure complete sterilization, as it may not allow the steam to effectively penetrate the materials.

**Clinical Pearl / High-Yield Fact**
To ensure effective autoclaving, it is essential to follow the recommended conditions, including temperature, pressure, and holding time. Failure to do so may result in incomplete sterilization and potentially lead to the spread of infection.

**Correct Answer: C. Holding time of 15-20 minutes.**