Due to a limitation in the backend system, a system API can only handle up...

Explanation

Correct Answer: Spike control

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>> First things first, HTTP Caching policy is for purposes different than avoiding the backend system from overloading. So this is OUT.

>> Rate Limiting and Throttling/ Spike Control policies are designed to limit API access, but have different intentions.

>> Rate limiting protects an API by applying a hard limit on its access.

>> Throttling/ Spike Control shapes API access by smoothing spikes in traffic.

That is why, Spike Control is the right option.