Universal Containers created a custom object called Defect and would like to enable the Sharing button on the Defect page layout to share the records manually to other users in the organization. In which scenario will the Sharing button appear?

What should the Architect do to ensure Field-Level Security is enforced on a custom Visualforce page using the Standard Lead Controller?

Cosmic Service Solutions has three branches in the role hierarchy for the three regions in the United States where it provides support services to other companies. The organization-wide default sharing setting of the Case object has been set to 'Private'. When working on case resolution, the support agents in the western branch should be able to collaborate by sharing case records with the support agents in the central branch of the hierarchy. No other users in the company, including the managers, should be able to gain access to these records. What can a Salesforce Architect recommend to meet this requirement?Choose 1 answer.

When you make changes to roles and groups Salesforce locks the entire group membership table, which makes it impossible to process group changes in multiple threads to increase throughput on updates.

Universal Container (UC) wants all full-time internal employees to be able to view all leads. A subset of employees should also be able to see leads.
Which organization default (OWD) approach should an architect recommend that will help US employee?