The host command in Linux is used for DNS lookup operations. The switch -t specifies the type of DNS record you are querying.

host -t a domain.com queries for A (Address) records, which return the IP address associated with a domain.

host -t ns queries for name servers (NS records).

host -t soa queries for the Start of Authority (SOA) record.

host -t AXFR attempts a zone transfer (not a standard resolution method and typically blocked).

Hence, option A correctly resolves a domain name to its IP address.