https://www.darknet.org.uk/2017/07/bluto-dns-recon-zone-transfer-brute-forcer/
"Attackers also use DNS lookup tools such as DNSdumpster.com, Bluto, and Domain Dossier to retrieve DNS records for a specified domain or hostname. These tools retrieve information such as domains and IP addresses, domain Whois records, DNS records, and network Whois records." CEH Module 02 Page 138

This activity most accurately describes a DHCP starvation attack. CEH network and sniffing coverage explains that DHCP starvation is a denial-of-service technique in which an attacker rapidly sends large numbers of DHCP requests, usually with spoofed MAC addresses, to consume all available IP addresses in the DHCP pool. Once the pool is exhausted, legitimate clients can no longer obtain valid leases, which produces exactly the symptoms described in the question: repeated address negotiation attempts, failure to receive configuration, and a burst of requests coming from a single interface. A rogue DHCP server is often paired with starvation later, but the key evidence here is the rapid exhaustion behavior rather than the distribution of malicious configurations. IRDP spoofing would manipulate gateway discovery, not primarily deplete DHCP leases, and MAC spoofing alone would not explain widespread address assignment failure across multiple hosts. CEH guidance presents DHCP starvation as both a network disruption issue and a stepping stone for further interception attacks, since denying legitimate DHCP service can set conditions for a rogue DHCP server to take over client configuration and redirect traffic.

CEH v13 states that the only viable way to attack WPA2-PSK is by capturing the four-way handshake. De- authentication forces clients to reconnect, allowing the handshake to be captured and later cracked offline.
MITM, jamming, and rogue AP attacks do not directly expose the PSK.

Zero-day exploits are considered the most dangerous mobile attack vector in CEH v13 Mobile Platform Hacking. These exploits abuse previously unknown vulnerabilities, meaning no patches, signatures, or defenses exist at the time of attack.
In healthcare environments, mobile devices access sensitive EHR systems and operate under strict compliance requirements. Zero-day exploits can bypass mobile OS security, sandboxing, and antivirus controls entirely.
App spoofing and Bluejacking are easier to detect and mitigate through user awareness and Bluetooth controls. Side-channel attacks are highly specialized and rare in enterprise mobile environments.
CEH v13 stresses that zero-day attacks pose the greatest risk due to lack of detection mechanisms, making Option A correct.