Explanation
In a Zero downtime upgrade, you should upgrade the Standby Member first. This is because the Standby Member does not process traffic and can be upgraded without affecting the cluster availability. After upgrading the Standby Member, you can perform a failover and make it the Active Member. Then you can upgrade the original Active Member, which becomes the Standby Member after the failover.
References: Getting Started - Check Point Software, section "Upgrading Cluster Members with Zero Downtime"

Explanation
The correct steps to configure the HTTPS Inspection Policy in Check Point R81 are as follows1:
Go to Manage&Settings > in SmartDashboard.
Enable HTTPS Inspection and select the
Create a new HTTPS Inspection Layer
Define the rules for inspecting HTTPS traffic based on the source, destination, service, and action.
Install the policy on the relevant gateways.
The other options are incorrect because they either use wrong blade names, wrong menu options, or wrong configuration steps. References: 1: LAB:25 How to Configure HTTPS Inspection in Check Point Firewall R81(https://www.youtube.com/watch?v=NCvV7-R9ZgU)

Explanation
If an administrator wants to add manual NAT for addresses not owned by the Check Point firewall, they also need to add the proxy ARP configurations in a file called $FWDIR/conf/local.arp. This file contains the mappings between the IP addresses and the MAC addresses of the NATed hosts. The proxy ARP feature allows the firewall to answer ARP requests on behalf of the NATed hosts and forward the traffic to them. The local.arp file needs to be edited manually and reloaded with the command arp -f $FWDIR/conf/local.arp.
References: R81 Security Management Administration Guide, page 1014.