Explanation
Policy Types are the different types of security policies that can be configured and enforced on a Check Point gateway. The valid Policy Types in R81.X are:
Access Control: Defines the rules for allowing or blocking traffic based on source, destination, service, user, and other criteria.
IPS: Protects the network from known and unknown attacks by inspecting the traffic and applying signatures, protections, and actions.
QoS: Controls the bandwidth allocation and prioritization for different types of traffic and applications.
DLP: Prevents the leakage of sensitive data from the network by detecting and blocking data transfers that violate predefined rules.
The references are:
Check Point Certified Security Expert R81.20 (CCSE) Core Training, slide 11 Check Point Certified Security Administrator R81 - ExperTeach, page 5 Check Point Cybersecurity BootCamp R81.20 - CCSA & CCSE Training, page 2

https://sc1.checkpoint.com/documents/R81/WebAdminGuides/EN/CP_R81_CLI_ReferenceGuide/Topics-CLIG/FWG/fw-monitor.htm i (for example, eth4:i) Pre-Inbound - Before the inbound FireWall VM E (for example, eth4:E) Post-Outbound - VPN Outbound after encrypt

Explanation
Check Point recommends configuring Disk Space Management parameters to delete old log entries when available disk space is less than or equal to a certain threshold. In this case, the correct threshold is specified as option D: 15%.
So, when the available disk space reaches or falls below 15%, old log entries should be deleted to free up space.
Options A, B, and C do not represent the recommended threshold for deleting old log entries according to Check Point's best practices.
References: Check Point Certified Security Expert (CCSE) R81 documentation and learning resources.

The Hit Count feature allows tracking the number of connections that each rule matches, regardless of the Track option set for the rule. When you enable Hit Count, the Security Management Server collects the data from supported Security Gateways and displays it in SmartConsole. You can use the Hit Count feature to optimize your rule base by identifying unused or rarely used rules, or rules that match too many connections.