Reference:
https://docs.cloud.oracle.com/en-us/iaas/Content/Identity/Tasks/managingcredentials.htm

Explanation
NFS export options enable you to create more granular access control than is possible using just security list rules to limit VCN access. You can use NFS export options to specify access levels for IP addresses or CIDR blocks connecting to file systems through exports in a mount target.

in ADW, The tnsnames.ora file provided with the credentials zip file contains three database service names identifiable as high, medium, and low. The predefined service names provide different levels of performance and concurrency for Autonomous Data Warehouse.
high: The High database service provides the highest level of resources to each SQL statement resulting in the highest performance, but supports the fewest number of concurrent SQL statements. Any SQL statement in this service can use all the CPU and IO resources in your database. The number of concurrent SQL statements that can be run in this service is 3, this number is independent of the number of OCPUs in your database.
medium: The Medium database service provides a lower level of resources to each SQL statement potentially resulting a lower level of performance, but supports more concurrent SQL statements. Any SQL statement in this service can use multiple CPU and IO resources in your database. The number of concurrent SQL statements that can be run in this service depends on the number of OCPUs in your database.
low: The Low database service provides the least level of resources to each SQL statement, but supports the most number of concurrent SQL statements. Any SQL statement in this service can use a single CPU and multiple IO resources in your database. The number of concurrent SQL statements that can be run in this service can be up to 300 times the number of OCPUs.
The predefined service names provide different levels of performance and concurrency for Autonomous DB Choose whichever database service offers the best balance of performance and concurrency.
Use the low database service name. to minimize the impact of their SQLs to by low consumer group

Explanation
Data Guard in Maximum Performance protection mode is supported not simply Maximum Protection mode, however, you can configure additional protection modes and transport types by logging on to the DB system and accessing Data Guard command-line interface( DGMGRL).

Explanation
To accept traffic from the internet, you create a public load balancer. The service assigns it a public IP address that serves as the entry point for incoming traffic. You can associate the public IP address with a friendly DNS name through any DNS vendor.
A public load balancer is regional in scope. If your region includes multiple availability domains, a public load balancer requires either a regional subnet (recommended) or two availability domain-specific (AD-specific) subnets, each in a separate availability domain. With a regional subnet, the Load Balancing service creates a primary load balancer and a standby load balancer, each in a different availability domain, to ensure accessibility even during an availability domain outage. If you create a load balancer in two AD-specific subnets, one subnet hosts the primary load balancer and the other hosts a standby load balancer. If the primary load balancer fails, the public IP address switches to the secondary load balancer. The service treats the two load balancers as equivalent and you cannot specify which one is "primary".
Whether you use regional or AD-specific subnets, each load balancer requires one private IP address from its host subnet. The Load Balancing service supplies a floating public IP address to the primary load balancer.
The floating public IP address does not come from your backend subnets.
You cannot specify a private subnet for your public load balancer.
The backend servers (Compute instances) associated with a backend set can exist anywhere, as long as the associated network security groups (NSGs), security lists, and route tables allow the intended traffic flow.
Oracle recommends that you create your load balancer in a regional subnet.
Oracle recommends that you distribute your backend servers across all availability domains within the region.