Implementing JIRA Data Center involves key components like load balancer for distributing traffic, shared file system for shared data storage, database replication for data synchronization, and clustering for high availability. These architectural changes are essential for achieving scalability and ensuring uninterrupted service.

When creating a new issue type in JIRA, administrators have the ability to define custom fields. These custom fields can capture specific information relevant to the new issue type, allowing for greater flexibility and customization within the JIRA instance.

You can create a new Automation Rule in JIRA by accessing the Project Settings, then selecting Automation, and finally creating a new rule from there. This allows users to define the conditions and actions for their automation rules without needing to modify the JIRA source code or seek external support.

In JIRA, an issue can have one or more assignees assigned to it. Assignees are individuals responsible for working on the issue. Multiple assignees can be assigned to an issue to distribute work among team members efficiently.

In Agile methodology, the product backlog consists of user stories, which are concise descriptions of desired functionality from an end user's perspective, prioritized based on business value.

Triggers in JIRA Automation are used to initiate actions when certain events occur. These events could include issue creation, transition, or comment addition, among others. Rules encompass both conditions and actions, where conditions define when the rule should execute, and actions specify what tasks should be performed.

The "JIRA Administrators" group in JIRA's default configuration is responsible for managing global JIRA settings and users. Members of this group have extensive privileges, including the ability to configure system-wide settings, manage user accounts, and perform administrative tasks across all projects in the JIRA instance. This group plays a crucial role in maintaining the integrity and functionality of the JIRA environment.

The "Epic" issue type in JIRA is often utilized to represent high-level initiatives or goals that span multiple projects. Epics provide a way to group related tasks, stories, or other issues together, allowing teams to track progress and dependencies at a higher level of abstraction.

A "security scheme" in JIRA is used to manage Issue permissions and access controls. These schemes allow administrators to control who can view, edit, and perform various actions on issues within a project. By configuring security schemes, organizations can ensure that sensitive information is protected and access is restricted as needed. Thus, option 2 is correct.

To create a filter subscription in JIRA, you need to navigate to the Filters menu, select the desired filter, and then click on "Subscribe." From there, you can configure the frequency and recipients for email updates based on the filter results.