What is the purpose of a Role in Salesforce?

Correct answer: To define a hierarchy for data sharing and visibility

Option D is correct because a Role in Salesforce defines where a user sits in the organizational hierarchy, which determines record visibility through the Role Hierarchy sharing model, allowing managers and executives to see records owned by users below them. Option A is incorrect because which objects a user can access is controlled by their profile or permission sets, not their Role. Option B is incorrect because field-level security, which restricts visibility and editability of individual fields, is configured in profiles and permission sets, not Roles. Option C is incorrect because session timeout values are an authentication setting configured at the profile or organization level, not related to the Role object.