Which Anypoint Platform component should a MuleSoft developer use to create an API specification prior to building the API implementation?

Refer to the exhibit.

An organization is sizing an Anypoint VPC for the non-production deployments of those Mule applications that connect to the organization's on-premises systems. This applies to approx. 60 Mule applications. Each application is deployed to two CloudHub i workers. The organization currently has three non-production environments (DEV, SIT and UAT) that share this VPC. The AWS region of the VPC has two AZs.
The organization has a very mature DevOps approach which automatically progresses each application through all non-production environments before automatically deploying to production. This process results in several Mule application deployments per hour, using CloudHub's normal zero-downtime deployment feature.
What is a CIDR block for this VPC that results in the smallest usable private IP address range?

What is true about the network connections when a Mule application uses a JMS connector to interact with a JMS provider (message broker)?

Which Anypoint Platform component helps integration developers discovers and share reusable APIs, connectors, and templates?

Refer to the exhibit.
A Mule application is being designed to be deployed to several CIoudHub workers. The Mule application's integration logic is to replicate changed Accounts from Satesforce to a backend system every 5 minutes.
A watermark will be used to only retrieve those Satesforce Accounts that have been modified since the last time the integration logic ran.
What is the most appropriate way to implement persistence for the watermark in order to support the required data replication integration logic?