正解:A
Proxy caching is a method that enables a proxy server to save recent and frequent website/webpage requests and data requested by one or more client machines. It reduces latency, eases bandwidth consumption, and ensures content is served more swiftly to the end-user12. WSA (Web Security Appliance) is a Cisco product that provides proxy caching functionality, along with other web security features such as malware protection, URL filtering, and data loss prevention3. Firepower, FireSIGHT, and ASA are other Cisco products that do not provide proxy caching, but rather focus on different aspects of network security, such as threat detection, management, and firewall . References:
* What is Proxy Caching? | StackPath
* What Is Proxy Caching? | Definition & Overview | NinjaOne
* Cisco Web Security Appliance Data Sheet
* [Cisco Firepower NGFW Data Sheet]
* [Cisco FireSIGHT Management Center Data Sheet]
* [Cisco ASA 5500-X Series Firewalls Data Sheet]