Explanation
The Product admin role for Jira Administration is only available for groups that have access to Jira Software1.
The "confluence-admins" group does not have access to Jira Software by default, so you cannot grant them this role. You can only grant this role to groups that have the Jira Software User role or the Jira Software Admin role2.
References:
Manage groups
Manage product roles

Explanation
If you want to manage users and groups from both corporations in a single location, you need to consolidate your Atlassian Cloud organizations. This can be done by transferring all product instances in one organization to another. After the transfer, the unwanted organization is deleted1. This feature is called Transfer products and it is available from the organization settings2.
The other options are not features that can help you merge your organizations. Organization insights is a feature that provides analytics and reports on your organization's users, products, and security3. Release tracks is a feature that allows you to choose when your cloud products receive new features and improvements4. Verify domains is a feature that allows you to manage the Atlassian accounts of your users and apply security policies to them5. Identity providers is a feature that allows you to integrate your organization with external identity services, such as SAML or SCIM6.
References :
Should I merge my Atlassian organizations?
Transfer all products to another organization
View organization insights
Choose a release track for your cloud products
Verify a domain to manage accounts
Manage users from your identity provider

Explanation
This statement is false because every site belongs to an organization. When you create a new site, you either join an existing organization or create a new one1. You cannot have a site without an organization.
References: Get started with an Atlassian organization, Understand Atlassian sites and organizations

Explanation
By default, Jira Software creates two groups: jira-software-users and jira-software-admins. The jira-software-users group is granted the Jira Software User role, and the jira-software-admins group is granted the Jira Software Admin role. These roles determine the permissions and access that the group members have within Jira Software. The default groups also have a suffix that matches the site name, in this case
"ewok7a". Therefore, the default groups for Jira Software on the "ewok7a" cloud site are jira-software-users-ewok7a and jira-software-admins-ewok7a, as shown in Option A12 References = Manage product access, Manage project roles

Explanation
When a user is invited to join a product or site, they automatically get an Atlassian account. The status
"Invited" means that the user has not accepted the invitation yet, but they already have an account created for them.
References:
Accept the invitation to join your service project team
Customer is not receiving invitation emails when invited to a Service Management project