Final answer:
Filtration is the best method to sterilize heat-labile solutions, as it removes microbes physically without the use of damaging high temperatures, unlike autoclaving, boiling, or incineration.
Step-by-step explanation:
The best method to sterilize heat-labile solutions is filtration. Unlike methods such as boiling, autoclaving, and incineration, filtration does not involve high temperatures that could denature or degrade heat-sensitive components within the solution. Filtration physically removes microbes from the solution without exposing it to heat.
While the autoclave is considered the most effective method of sterilization for items that can withstand high temperatures, it is not suitable for heat-labile solutions as it uses moist-heat sterilization at temperatures above the boiling point of water. Similarly, boiling water and incineration are also inappropriate for sterilizing heat-sensitive solutions due to their reliance on high temperatures. Since the question specifies the sterilization of heat-labile solutions, filtration remains the best choice.