A suspected cyber-criminal was captured, and his computer was seized while he was online.

Option D is the best answer because the computer was seized while the Tor Browser was actively open , meaning the most valuable evidence may still exist in volatile memory . In CHFI methodology, when a live system contains potentially crucial active-session evidence, investigators should follow the order of volatility and collect the most easily lost evidence first. A memory dump may preserve active browser session data, in-memory artifacts, decrypted content, process information, network connections, and traces of recently accessed dark web activity that might never be written clearly to disk.

Shutting down or unplugging the machine would destroy this volatile evidence immediately. Restarting into safe mode would also alter or erase the active session context. Hard drive analysis remains important later, but it would not capture the full live state of the Tor session as effectively as RAM collection.

Because the goal is to obtain as much information as possible from the active session , the strongest CHFI-aligned answer is to leave the system running and collect a memory dump first before taking further acquisition steps.