Explanation:

In Microsoft Sentinel (Log Analytics), table retention uses two tiers: Interactive retention (hot, immediately queryable) and Archive (cold, queryable via Search/Restore). Sentinel includes up to 90 days of interactive retention at no additional cost; extending interactive retention beyond 90 days incurs standard Log Analytics retention charges. To minimize cost, you should keep the interactive period at 90 days (the free tier).
For longer-term availability of data while still controlling costs, you set a higher Total retention so that, after the interactive window, data is moved to Archive storage at a significantly lower price per GB. Archived data remains available to analysts using Search jobs or temporary Restore to hot for detailed queries.
Therefore, to maximize the period during which the table data remains available at the lowest cost, select the longest offered total retention, 2 years, which keeps older data in Archive instead of deleting it.
Thus, the optimal cost/availability configuration is Interactive = 90 days and Total = 2 years.