A company must archive customer correspondence PDFs that are rarely accessed but must be retained for seven years. The documents must be available for read within seconds if requested. Which Azure Blob Storage access tier should be used to minimize storage cost while meeting the availability requirement?
Cool tier is for infrequent access with immediate availability and lower storage cost than Hot.
Why this answer
The Cool tier is optimal because it balances low storage cost with high availability for data that is infrequently accessed but must be retrievable within seconds. It offers the same low-latency retrieval as the Hot tier (milliseconds) but at a lower storage price, making it ideal for archived correspondence that still requires immediate read access.
Exam trap
The trap here is that candidates see 'archived' and immediately choose the Archive tier, forgetting the 'within seconds' availability requirement that disqualifies it.
How to eliminate wrong answers
Option A is wrong because the Hot tier has the highest storage cost and is designed for frequently accessed data, not for rarely accessed archives. Option C is wrong because the Archive tier has the lowest storage cost but retrieval times can range from minutes to hours, failing the 'within seconds' requirement. Option D is wrong because the Premium tier is optimized for high transaction volumes and low latency on block blobs, not for cost-effective archiving of rarely accessed data.