Cache-aside (lazy loading) with a 45-second TTL is correct because it caches entries only after they are requested so the cache concentrates on hot profiles while the 45 second TTL bounds how stale data can become.

The Cache-aside (lazy loading) with a 45-second TTL pattern avoids populating memory with cold accounts because items are added on demand. The short TTL ensures cached profiles are evicted or refreshed frequently so reads remain within the tolerated staleness window for the social feed.

Write-through with TTL is not ideal because it populates the cache on every write and that behavior can fill limited cache capacity with profiles that are never read even though TTL limits staleness.

Write-through without TTL is not appropriate because it keeps every written profile in cache indefinitely and that risks serving stale data beyond the acceptable 45 seconds while also wasting memory on cold records.

Cache-aside (lazy loading) without TTL focuses the cache on hot keys but lacks an expiration mechanism and so cached entries can remain stale longer than the allowed freshness window.

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