Which consistency level allows for immediate data writes but varying latencies in updates?

The correct choice is session consistency. This consistency level is designed to provide a balance between immediate data write availability and a degree of consistency that does not require all updates to be immediately visible to all clients. In session consistency, a client is guaranteed to see its own writes immediately, ensuring that any operations performed by the same session will reflect the most current state of data.

However, this does not guarantee that all clients will see the same updates immediately. Other clients might get stale data for a time, allowing for varying latencies in how quickly they receive updates. This model is particularly useful in scenarios where user interactions are common, since it prioritizes a responsive experience for the individual user while still allowing some flexibility in how data is propagated across the system.

The other options focus on different aspects of consistency. Strong consistency ensures that all users see the most recent write at all times, which can introduce latency. Eventual consistency allows for updates to propagate through the system over time, where clients might not see changes immediately but will eventually converge to the same state. Bounded consistency provides a compromise that ensures the system converges within a certain timeframe but does not guarantee immediate visibility to updates across all clients.