If you only know DNS as "converting domain names to IPs," you understand less than half of Route 53. AWS designed Route 53 not as a simple DNS resolver but as a traffic routing engine. The 7 routing policies each use different algorithms to decide which endpoint to respond with. In SAP-C02, if you can't precisely distinguish these 7 types, you make mistakes like choosing Geolocation for "closest region" problems or Latency for "country-based isolation" problems.
Today we understand why each policy works the way it does—at the level of internal algorithms and DNS protocol—and complete the reasoning for scenario judgment.