At UVC, the Account object has a MD relationship with an Invoice custom object. The app builder would like to change this to a lookup field, but is not able to do so. What could be causing this?

To increase adoption, Universal Containers is proposing changes to its Salesforce data model to allow easier visibility for sales reps into key metrics. The proposal has three custom objects related to the Account object, one with a master-detail, and two that are not. Each of these objects has 15 fields they would like to summarize on the Account object.
What are two considerations for this proposal?
Choose 2 answers

Universal containers uses a custom called reviews to capture information generated by interviews during the candidate process. The review records are visible to any user that has access to the related custom candidate record. The VP of human resources wants the comment field on the review to be private to anyone outside of the HR department.

Universal Containers has two types of applicants, hourly and salary. There are separate record types for each. While all members of the human resource department need to be able to view all applicant records, only the hiring Manager and VP of HR should be able to create salary applicant records.
What should the app builder recommend to meet this requirement?

Universal Containers has a requirement that an Opportunity should have a field showing the value of its associated account's billing state. This value should not change after the Opportunity has been created.
What is the recommended solution to configure this automation behavior?