The correct answer is C. AppExchange package.
The key word is daily. Salesforce's native Data Export Service supports manual and scheduled exports, but Salesforce documentation states that backup files can be generated manually once every 7 days for weekly export or 29 days for monthly export, depending on edition. That does not meet an automatic daily backup requirement.
For daily automated backups, the app builder should recommend a backup solution from AppExchange.
Report export is not an org backup, and refreshing a full copy sandbox is not a backup automation tool.

The correct answer is C. The user wants to update the related Account directly from the Opportunity page.
The proper declarative solution is to create an Update a Record quick action for Account and expose it through the Related Record component on the Opportunity Lightning record page. Salesforce documentation identifies Related Record as a standard Lightning page component and notes that quick actions such as Create a Record and Update a Record are supported in Lightning page experiences.
Why others are incorrect:
A updates fields through automation, but the user wants to edit directly.
B formula fields are read-only.
D the Record Detail component is for the current record, not editing a related Account from Opportunity.

The correct answer is B. Validation Rule.
DreamHouse Realty wants to prevent an Opportunity from entering the Qualified stage unless Expected_Close_Date__c is populated. A validation rule is the correct tool because Salesforce validation rules check whether record data meets specified criteria before the user can save the record.
A validation rule could check:
Stage = Qualified
AND
Expected_Close_Date__c is blank
If both are true, Salesforce blocks the save and displays an error message.
A). Page Layout can make a field visible or required on a layout, but it cannot conditionally require the field only when Stage equals Qualified.
C). Activity History is unrelated.
D). Record Type controls business processes and layouts but does not enforce this condition by itself.

The correct answer is A because Case_Issue__c is described as a junction object. In Salesforce, a junction object is typically built with two master-detail relationships to model a many-to-many relationship.
Salesforce documentation states that sharing access to a junction object record is determined by the user's sharing access to both associated master records and the sharing setting on the relationship fields.
So, for auditing users to view Case_Issue__c records, they need read access to both parent/master records:
Case and Issue__c.
Why others are incorrect:
B misses access to Issue__c.
C includes only the junction object and misses both parent/master records.
D misses access to Case.

A Global Picklist Value Set is used when the same picklist values must be reused across multiple objects and fields. Salesforce states that global picklist value sets let admins share values across objects and custom picklist fields.
Why not others:
A). Shared Custom Field is not a Salesforce feature for this requirement.
C). Dependent Picklist controls values based on another field.
D). Related Picklist is not the correct Salesforce feature.