The correct answer is C. Whois lookup because the scenario describes retrieving publicly available domain registration records using an online service without directly interacting with the target organization's infrastructure. In CEH-aligned reconnaissance (footprinting) techniques, WHOIS is a foundational passive information-gathering method used to identify details tied to a domain name, such as the registrant
/organization, administrative and technical contacts, registration and expiration dates, and the authoritative name servers associated with the domain. These details are commonly used to establish ownership context, map the organization's external footprint, and identify potential points of contact for administrative or security coordination.
The prompt emphasizes that the ethical hacker wants "details about the organization's domain ownership" and
"points of contact." That is precisely the kind of information WHOIS is intended to provide. It also explicitly notes "without direct interaction with the target," which aligns with WHOIS being passive: queries are made to registries/registrars or WHOIS aggregation services rather than probing the target's servers.
Why the other options are less correct: Email footprinting focuses on collecting email addresses, formats, mail servers, and potentially related metadata, but it is not the primary method for domain ownership/registrant contact records. Network footprinting is broader and often involves identifying IP ranges, network blocks, technologies, and topology-potentially including active probing. DNS interrogation (such as querying A, MX, NS, TXT records) can reveal technical DNS data and infrastructure mapping, but it typically does not provide the domain's registrant ownership details and formal contact records; that role is handled by WHOIS and registry data.
Therefore, the method most likely used here is a WHOIS lookup to obtain public domain registration and contact information.

STP prevents bridging loops in a redundant switched network environment. By avoiding loops, you can ensure that broadcast traffic does not become a traffic storm.
STP is a hierarchical tree-like topology with a "root" switch at the top. A switch is elected as root based on the lowest configured priority of any switch (0 through 65,535). When a switch boots up, it begins a process of identifying other switches and determining the root bridge. After a root bridge is elected, the topology is established from its perspective of the connectivity. The switches determine the path to the root bridge, and all redundant paths are blocked. STP sends configuration and topology change notifications and acknowledgments (TCN/TCA) using bridge protocol data units (BPDU).
An STP attack involves an attacker spoofing the root bridge in the topology. The attacker broadcasts out an STP configuration/topology change BPDU in an attempt to force an STP recalculation. The BPDU sent out announces that the attacker's system has a lower bridge priority. The attacker can then see a variety of frames forwarded from other switches to it. STP recalculation may also cause a denial-of-service (DoS) condition on the network by causing an interruption of 30 to 45 seconds each time the root bridge changes. An attacker using STP network topology changes to force its host to be elected as the root bridge.

switch

The capabilities described match an enterprise Wireless Intrusion Prevention System (WIPS) tightly integrated with WLAN infrastructure: it uses access points as sensors (placing selected APs into passive scan
/monitor mode), correlates and aggregates alarms from multiple controllers into a central engine for analysis and forensic retention, and can push automated countermeasures across the campus (such as coordinated channel scanning and remote configuration enforcement) when a device is classified as malicious. This is most consistent with Cisco Adaptive Wireless IPS.
Cisco's adaptive WIPS model uses the existing Cisco wireless architecture (controllers and APs) to provide campus-wide monitoring and enforcement. The phrase "selected APs into a passive scan mode" is a strong indicator of adaptive sensor use-APs can be dedicated or time-sliced for scanning, and the system can coordinate coverage across channels. The centralized engine concept also aligns with enterprise WIPS deployments that collect events and alarms from multiple controllers for correlation and long-term storage, supporting incident investigation and compliance.
Why the other options are less fitting:
Fern WiFi Cracker (C) is an attack/assessment tool, not a production defensive platform, and it does not provide centralized alarm aggregation and automated enterprise countermeasures.
RFProtect (B) is a known wireless security/WIPS solution family, but the question's feature set and wording ("adaptive," APs used for passive scanning, controller-integrated countermeasures) most closely matches Cisco's adaptive WIPS concept.
WatchGuard Wi-Fi Cloud WIPS (A) is a vendor-managed WIPS offering; while it can provide monitoring, the scenario stresses multi-controller aggregation into a central engine and coordinated campus countermeasures via WLAN infrastructure-again aligning best with Cisco's controller/AP ecosystem.
Therefore, the best answer is D. Cisco Adaptive Wireless IPS.

CEH materials describe RDDoS (Ransom DDoS) attacks as threat-driven extortion campaigns where attackers demand payment and demonstrate capability by launching a short-lived DDoS burst. The purpose is to intimidate the victim into paying before a larger, sustained attack begins. The attack described uses HTTP floods with incomplete POST requests-an application-layer DDoS technique that consumes server resources by forcing the target to hold open connections. This kind of demonstration followed by an extortion email aligns precisely with RDDoS behavior. DRDoS attacks involve reflection/amplification through third-party servers, which is not occurring here. Pulse wave attacks use timed bursts and do not involve extortion, while recursive GET floods do not match the incomplete POST behavior. Therefore, the correct classification is RDDoS.