Final answer:
Spore testing is an essential method for ensuring sterilization effectiveness.
Step-by-step explanation:
The correct answer is c. Spore testing is an essential method for ensuring sterilization effectiveness. Spore testing involves using biological indicators, such as strips or tubes containing spores of bacteria that are highly resistant to heat, to determine whether the sterilization process has been successful. These spores are incubated after sterilization to check for any remaining viable spores. This method is important for validating the effectiveness of sterilization protocols in various settings, including medical, laboratory, and manufacturing.