The CEH Footprinting and Reconnaissance module describes DNS interrogation as a valuable technique for extracting publicly available infrastructure information such as A records, MX records, NS records, and subdomains.

DNS can reveal:

Subdomains (via zone transfers, brute forcing, or enumeration)

Mail server IP addresses (MX records)

Server locations inferred from IP geolocation

However, DNS does not store authentication credentials. Usernames and passwords are protected within authentication systems and directories, not DNS records.

Therefore, option A is correct.

CEH clearly states that DNS reconnaissance is limited to infrastructure metadata, not sensitive user credentials.