According to theCHFI v11 Mobile and IoT Forensicsdomain, thepreservation stageis specifically responsible for ensuring that digital evidence remainsunaltered, intact, and legally admissiblethroughout the forensic lifecycle. Preservation beginsimmediately after evidence is identifiedand continues until the investigation is concluded and evidence is presented in court.

In IoT investigations, preservation is especially critical because IoT devices—such as smart locks, cameras, sensors, and hubs—often containvolatile data, limited storage, and continuous network connectivity. CHFI v11 emphasizes that investigators must take steps such asisolating devices from networks, disabling remote access, preventing firmware updates, maintaining power states when necessary, and documenting handling proceduresto avoid unintentional data modification or loss.

Whileevidence identification and collectionfocuses on locating and acquiring devices and data sources, it does not by itself guarantee protection against alteration.Data analysisandpresentation/reportingoccur later and rely on evidence that has already been preserved correctly. Any failure in preservation can compromise chain of custody and result in evidence being challenged or excluded.

CHFI v11 explicitly states thatpreservation safeguards evidence integrity before, during, and after collection, making it the foundation of a defensible IoT forensic investigation.

Therefore, the stage that ensures evidence integrity by preventing alteration before collection isPreservation, makingOption Dthe correct and CHFI v11–verified answer.