Final answer:
option 2.In Salesforce, 'Roles and Subordinates' is the option that most accurately represents what comprises public groups because it includes a role and all the roles that are hierarchically below it.
Step-by-step explanation:
In Salesforce, public groups consist of collections of users, but the specific options provided need clarifying. While neither roles nor profiles are considered public groups in their own right, the option labeled 'Roles and Subordinates' does indeed approximate what can be considered a public group. This option includes a role and all the subordinated roles that roll up to it, making it a form of a public group that dictates the level of access users have based on their position in the role hierarchy.
Therefore, among the given options, 'Roles and Subordinates' is the choice that most closely aligns with the composition of public groups in Salesforce. This is because public groups in Salesforce can be used to represent a collection of users that can be based on roles, subsets of users, or a combination of these and other criteria to facilitate sharing and access permissions across the platform.