What are two correct examples of the model in the salesforce MVC architecture? Choose 2 answers.

A developer needs to prevent the creation of Request_c records when certain conditions exist in the system. A RequestLogic class exists to checks the conditions. What is the correct implementation?

Which option should a developer use to create 500 Accounts and make sure that duplicates are not created for existing Account Sites?

A developer needs to provide a way to mass edit, update, and delete records from a list view. In which two ways can this be accomplished? Choose 2 answers

Given the following code snippet, that is part of a custom controller for a Visualforce page:

In which two ways can the try/catch be enclosed to enforce object and field-level permissions and prevent the DML statement from being executed if the current logged-in user does not have the appropriate level of access? Choose 2 answers