When activating a page in the Lightning app builder, what declarative options are available? (Choose three.)

Universal Containers uses a private sharing model for opportunities. This model cannot be changed due to a regional structure. A new sales operations team has been created. This team needs to perform analysis on Opportunity data, and should have read and write access to all Opportunities.
Which two are recommended solutions for the app builder to give the users appropriate access? (Choose two.)

An app builder at Universal Containers would like to prevent users from creating new records on an Account related list by overriding standard buttons.
Which two should the app builder consider before overriding standard buttons? (Choose two.)

An app builder is loading data into Salesforce. To link new records back to the legacy system, a field will be used to track the legacy ID on the Account object. For future data loads this ID will be used when upserting records.
Which two fields attributes should be selected? (Choose two.)

A junction object has two Master-Detail relationships, a primary and a secondary master object.
What happens to a junction object record when both associated master records are deleted?