Spatial Prepositions in System Descriptions

From / through / into is correct. This follows the natural sequence of spatial prepositions for data flow: from (origin) → through (passage/process) → into (destination/final container). "Data flows from the ingestion layer through the transformation pipeline into the data warehouse" is the canonical architecture description pattern. Mixing these up reverses the logic of the pipeline.

Between is correct. "Between services" is used when referring to the interactions of multiple distinct services with each other. "Between" expresses the mutual, bidirectional relationship in a network of components. Within would mean "inside a single service". Across would be used for spanning all services ("across all services"). Through describes passage, not relationship.

Across / within is correct. "Propagated across all nodes" means the configuration spreads to every node — "across" expresses distribution over all members of a set. "Within a few minutes" means before a few minutes have elapsed — "within" sets a time boundary. This is the standard phrasing for cluster configuration propagation. "Between all nodes" would be grammatical but unusual — "between" implies a mutual relationship, while "across" better captures uniform distribution.

From is correct. "Isolated from X" is the standard construction for expressing that a component is separated from a threat or network segment. The preposition "from" marks the thing being blocked or separated. Inside and within would describe a location, not a separation. Between implies two things relative to each other, not separation from something external.

Through is correct. "Routed through the load balancer" means the request passes via the load balancer — it enters, is processed, and exits to a destination. "Through" is the standard preposition for traffic that passes via an intermediary component. Across implies distribution. Between implies a mutual relationship between two endpoints. Into would suggest the request enters the load balancer and stays there.

Across is correct. "Replicated across three regions" means the service is distributed to multiple regions, covering all of them. "Across" expresses coverage of a set. Between would be used if there were exactly two regions. Within would mean inside a single region. Through would imply sequential passage, not distribution.

Within is correct. "Remain within the service layer" describes containment — the logic should stay inside a specific layer and not cross the boundary into another. Within is the preposition of internal containment. Across implies spanning multiple layers. Through implies passage. Between implies mutual relationship between two layers.

Option D is incorrect. "Stored into the cluster across the database" mixes spatial prepositions incorrectly. "Into" implies destination (the logs go into something), but "across the database" is confusing — logs are not stored "across" a database in standard usage. The correct form would be "stored in the database cluster" or "distributed across the cluster nodes". Options A, B, and C all use spatial prepositions correctly.

Across is correct. "Apply across all endpoints" means the rate limits span every endpoint without exception — uniform coverage of all members of a set. This is the standard phrasing for policies that apply universally. Within would imply the limits apply inside a specific scope. Into implies movement or direction. Between would imply a relationship between specific pairs of endpoints.

Into / through / into is correct. "Enters into the internet-facing load balancer" — into marks the point of entry. "Passes through the application tier" — through marks passage via a processing layer. "Persisted into the database cluster" — into marks the final destination where data is stored. This follows the canonical three-stage flow description for multi-tier architectures. The other options mix directional and distributional prepositions incorrectly.