A user tries to visit www.

The correct answer is Modify the CNAME record because a CNAME (Canonical Name) record maps one domain name (alias) to another domain name. If a user enters www.abc.com but is redirected to www.cba.com, it is likely that the DNS configuration includes an incorrect CNAME entry pointing abc.com to cba.com. Updating or correcting the CNAME record ensures the alias resolves to the intended host.

According to CompTIA Network+ (N10-009) objectives covering DNS record types, a CNAME record is used to alias one domain name to another, commonly for load balancing, CDN services, or website redirection.

A PTR record (Option B) is used for reverse DNS lookups (IP address to hostname) and does not control forward name resolution for websites. NTP settings (Option C) are used for time synchronization and have no impact on DNS resolution. A TXT record (Option D) stores descriptive text information (such as SPF, DKIM, or domain verification data) and does not affect website redirection.

Therefore, correcting the CNAME record resolves the issue and ensures users reach the correct website.