Which of the following verifies that autoclave sterilization has occurred?

The verification of autoclave sterilization involves confirming that the conditions necessary for effective sterilization have been met. A biological indicator is the most reliable method for this verification. It uses specific microorganisms known to be resistant to sterilization processes. After the sterilization cycle, the biological indicators are incubated to determine if any spores have survived. If there is no growth, it confirms that the autoclave was effective in killing those microorganisms, indicating successful sterilization.

While other options like chemical indicators and heat-sensitive tape provide some information about temperature and the presence of steam, they do not offer the same level of assurance as biological indicators. Chemical indicators can change color when exposed to certain conditions, but they don't confirm that sterilization has been achieved at a microbial level. Therefore, the biological indicator stands out as the gold standard for verifying that the sterilization process was effective.