Explanation
Controlling the invoices object permission on the sales manager's profile is how the architect can grant the sales managers access to the customer invoices data. Object permissions determine whether a user can create, read, edit, or delete any record of that object. Since invoice data is surfaced in Salesforce using external objects, sales managers need to have at least read permission on the invoice object to view the customer invoices data. Option A is incorrect, since sharing rules are not available for external objects. Option B is incorrect, since manual sharing is not available for external objects. Option D is incorrect, since sharing sets are not available for external objects.