**Core Concept**
Temperature and time are critical factors in sterilizing glassware using hot air. This method relies on the heat transfer to kill microorganisms, making it essential to choose an appropriate temperature.

**Why the Correct Answer is Right**
Hot air sterilization is often used for heat-stable items like glassware. The recommended temperature is 170-190°C for 1-2 hours. This temperature range is sufficient to kill most microorganisms, including bacterial spores, without damaging the glassware. The prolonged exposure ensures that all surfaces are effectively sterilized.

**Why Each Wrong Option is Incorrect**
**Option A:** 80°C - This temperature is too low to effectively sterilize glassware and would likely not kill all microorganisms, particularly bacterial spores.
**Option B:** 250°C - This temperature is too high and may damage or shatter the glassware, making it unsuitable for sterilization.
**Option C:** 120°C - This temperature is still too low to effectively sterilize glassware, and the time required would be impractically long.

**Clinical Pearl / High-Yield Fact**
When sterilizing glassware using hot air, it's essential to ensure that the temperature is consistent throughout the oven to prevent under- or over-sterilization.

**Correct Answer:** C. 170-190°C