Explanation:

The action "SiteRenamed" for SharePoint is covered under the AuditRetention4 policy, which applies to User1 and retains logs for 9 months.
The action "Send" for ExchangeItem is covered under the AuditRetention2 policy, but this policy applies only to User1. Since User2 is not covered under a specific policy, the default retention period for audit logs in Microsoft Purview is 90 days.