* Option A uses Shodan's API to gather information about a target without directly touching the target system. This makes it the stealthiest option as there's no traffic generated from the tester's IP to the target.
* Options B & D use Nmap which is active scanning, and while -T2 reduces intensity, it still generates packets.
* Option C is a custom curl script that also interacts directly with the target and can trigger IDS alerts.
CompTIA PenTest+ Reference:
* PT0-003 Objective 2.1 & 2.3: Passive vs Active reconnaissance techniques.
* Using OSINT sources like Shodan is a key stealth recon method.