The correct answer is A.
OBJ-3.1: A DNS zone transfer provides a full listing of DNS information. If your organization’s internal DNS server is improperly secured, an attacker can gather this information by performing a zone transfer. Fully qualified domain name (FQDN) resolution is a normal function of DNS that converts a domain name like www.diontraining.com to its corresponding IP address. Split horizon is a method of preventing a routing loop in a network. DNS poisoning is a type of attack which uses security gaps in the Domain Name System (DNS) protocol to redirect internet traffic to malicious websites.