Exam Certified Data Architect topic 1 question 129 discussion

A national nonprofit organization is using Salesforce to recruit members. The recruitment process requires a member to be matched with a volunteer opportunity. Given the following:

1. A record is created in Project__c and used to track the project through completion.
2. The member may then start volunteering and is required to track their volunteer hours, which is stored in VTOTime__c object related to the project.
3. Ability to view or edit the VTOTime__c object needs to be the same as the Project__c record.
4. Managers must see total hours volunteered while viewing the Project__c record.

Which data relationship should the data architect use to support this requirement when creating the custom VTOTime__c object?