The correct answer is D. SOA.
The SOA, or Start of Authority, record identifies the primary name server for a DNS zone and contains important administrative and technical information about that zone. The CEH reconnaissance reference states that the SOA record identifies the primary name server and contains the hostname of the server responsible for DNS records within the namespace, along with the basic properties of the domain .
The SOA record also provides zone metadata including:
Source host
Contact email
Serial number
Refresh time
Retry time
Expire time
TTL
These details match the question’s requirement to identify administrative and technical DNS metadata such as the serial number and refresh interval .
Option A. TXT is incorrect because TXT records usually store arbitrary text values, such as SPF, DKIM, DMARC, ownership verification, and other policy data. They do not provide zone authority metadata such as serial number or refresh interval.
Option B. MX is incorrect because MX records identify mail exchange servers for a domain, but they do not provide full zone administration details.
Option C. NS is incorrect because NS records identify authoritative name servers, but they do not include serial number, refresh time, retry time, expire time, or TTL values.
Option D. SOA is correct because it provides both the authoritative DNS information and administrative zone parameters needed during DNS reconnaissance.
Therefore, the best answer is D. SOA.
