In the context of HTTP caching, which statement describes how a cached response is retrieved?

• A. It uses a separate in-memory cache instead of an object store.
• B. It requires a backend call for every request.
• C. It only caches responses for GET requests.
• D. It searches for the key in the object store to retrieve a stored entry.

Answer: (D)

HTTP caching works by storing responses and retrieving them through a cache key. When a request arrives, the cache computes a key from the request (often the URL and related factors) and then searches the object store for an entry with that key. If a matching, fresh entry exists, the cached response is returned directly, avoiding a backend call. This lookup in the storage using the key is exactly how a cached response is retrieved. The other possibilities describe implementation details that aren’t required for retrieval: caches aren’t limited to in-memory only, a cache doesn’t have to call the backend for every request, and while GET is commonly cached, caching isn’t inherently limited to just GET requests.