Answer: Cloud DNS with DNSSEC

The question specifically asks for a service that authenticates responses to domain name lookups, which is the core function of DNSSEC (Domain Name System Security Extensions). Cloud DNS with DNSSEC provides cryptographic authentication of DNS responses, preventing DNS spoofing and cache poisoning attacks that could be used in DDoS scenarios. The community discussion shows 100% consensus on option A, with detailed explanations confirming that DNSSEC authenticates DNS lookups and protects against manipulation of DNS responses. Other options are less suitable: Cloud NAT (B) provides network address translation, HTTP(S) Load Balancing (C) distributes web traffic, and Google Cloud Armor (D) provides DDoS protection at the application layer but doesn't specifically authenticate DNS lookups.

Author: LeetQuiz Editorial Team